{"id":2667,"date":"2026-04-11T15:26:51","date_gmt":"2026-04-11T08:26:51","guid":{"rendered":"https:\/\/www.pgtutorial.com\/?page_id=2667"},"modified":"2026-04-11T15:38:26","modified_gmt":"2026-04-11T08:38:26","slug":"select","status":"publish","type":"page","link":"https:\/\/www.pgtutorial.com\/postgresql-python\/select\/","title":{"rendered":"PostgreSQL Python: Select Data from a Table with psycopg3"},"content":{"rendered":"\n<p><strong>Summary:<\/strong>&nbsp;In this tutorial, you&#8217;ll learn how to select one or multiple rows and filter rows from a table using&nbsp;<strong>Psycopg 3<\/strong>.<\/p>\n\n\n\n<p>Here are the steps for <a href=\"https:\/\/www.pgtutorial.com\/postgresql-tutorial\/postgresql-select\/\" type=\"page\" id=\"102\">retrieving data from a table<\/a> in PostgreSQL from Python:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>First, connect to PostgreSQL from Python.<\/li>\n\n\n\n<li>Next, create a&nbsp;<code>Cursor<\/code>&nbsp;object from the&nbsp;<code>Connection<\/code>&nbsp;object.<\/li>\n\n\n\n<li>Then, execute a&nbsp;<code>SELECT<\/code>&nbsp;statement by calling the&nbsp;<code>execute()<\/code>&nbsp;method of the cursor object<\/li>\n\n\n\n<li>After that, retrieve rows using&nbsp;<code>fetchone()<\/code>,&nbsp;<code>fetchall()<\/code>, or&nbsp;<code>fetchmany()<\/code>.<\/li>\n\n\n\n<li>Finally, process the returned rows in Python.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"prerequisites\" id='prerequisites'>Prerequisites <a href=\"#prerequisites\" class=\"anchor\" id=\"prerequisites\" title=\"Anchor for Prerequisites\">#<\/a><\/h2>\n\n\n\n<p>This tutorial assumes you already have a&nbsp;<code>products<\/code>&nbsp;table like this in the&nbsp;<code>pyinventory<\/code>&nbsp;database:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"SQL (Structured Query Language)\" data-shcb-language-slug=\"sql\"><span><code class=\"hljs language-sql\"><span class=\"hljs-keyword\">CREATE<\/span> <span class=\"hljs-keyword\">TABLE<\/span> <span class=\"hljs-keyword\">IF<\/span> <span class=\"hljs-keyword\">NOT<\/span> <span class=\"hljs-keyword\">EXISTS<\/span> products (\n    product_id <span class=\"hljs-built_in\">INT<\/span> <span class=\"hljs-keyword\">GENERATED<\/span> <span class=\"hljs-keyword\">ALWAYS<\/span> <span class=\"hljs-keyword\">AS<\/span> <span class=\"hljs-keyword\">IDENTITY<\/span> PRIMARY <span class=\"hljs-keyword\">KEY<\/span>,\n    <span class=\"hljs-keyword\">name<\/span> <span class=\"hljs-built_in\">VARCHAR<\/span>(<span class=\"hljs-number\">255<\/span>) <span class=\"hljs-keyword\">NOT<\/span> <span class=\"hljs-literal\">NULL<\/span>,\n    price <span class=\"hljs-built_in\">NUMERIC<\/span>(<span class=\"hljs-number\">10<\/span>, <span class=\"hljs-number\">2<\/span>) <span class=\"hljs-keyword\">NOT<\/span> <span class=\"hljs-literal\">NULL<\/span>,\n    safety_stock <span class=\"hljs-built_in\">INTEGER<\/span> <span class=\"hljs-keyword\">NOT<\/span> <span class=\"hljs-literal\">NULL<\/span>,\n    gross_weight <span class=\"hljs-built_in\">NUMERIC<\/span>(<span class=\"hljs-number\">10<\/span>, <span class=\"hljs-number\">2<\/span>)\n);<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">SQL (Structured Query Language)<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">sql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>It also assumes that the table already contains some data. If not, you can follow <a href=\"https:\/\/www.pgtutorial.com\/postgresql-python\/insert\/\" type=\"page\" id=\"2650\">this tutorial to insert some data into the table<\/a>:<\/p>\n\n\n<pre class=\"wp-block-code\"><span><code class=\"hljs\"> product_id |       name       |  price  | safety_stock | gross_weight\n------------+------------------+---------+--------------+--------------\n          3 | Pixel 7 Pro      |  899.99 |            8 |         0.21\n          4 | Xperia 1 IV      | 1299.99 |            7 |         0.19\n          2 | Galaxy S23 Ultra |  949.99 |            9 |         0.23\n          1 | iPhone 14 Pro    | 1199.99 |           20 |         0.24<\/code><\/span><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id=\"select-all-rows-from-a-table\" id='select-all-rows-from-a-table'>Select all rows from a table <a href=\"#select-all-rows-from-a-table\" class=\"anchor\" id=\"select-all-rows-from-a-table\" title=\"Anchor for Select all rows from a table\">#<\/a><\/h2>\n\n\n\n<p>The following script selects all rows from the&nbsp;<code>products<\/code>&nbsp;table:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">import<\/span> psycopg\n<span class=\"hljs-keyword\">from<\/span> config <span class=\"hljs-keyword\">import<\/span> config\n\nsql = <span class=\"hljs-string\">\"\"\"\nSELECT product_id, name, price, safety_stock, gross_weight\nFROM products\nORDER BY product_id\n\"\"\"<\/span>\n\n<span class=\"hljs-keyword\">try<\/span>:\n    <span class=\"hljs-keyword\">with<\/span> psycopg.connect(**config) <span class=\"hljs-keyword\">as<\/span> conn:\n        <span class=\"hljs-keyword\">with<\/span> conn.cursor() <span class=\"hljs-keyword\">as<\/span> cur:\n            cur.execute(sql)\n            rows = cur.fetchall()\n\n            <span class=\"hljs-keyword\">for<\/span> row <span class=\"hljs-keyword\">in<\/span> rows:\n                print(row)\n<span class=\"hljs-keyword\">except<\/span> Exception <span class=\"hljs-keyword\">as<\/span> e:\n    print(<span class=\"hljs-string\">f\"Error: <span class=\"hljs-subst\">{e}<\/span>\"<\/span>)\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Example output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">(<span class=\"hljs-number\">1<\/span>, <span class=\"hljs-string\">'iPhone 14 Pro'<\/span>, Decimal(<span class=\"hljs-string\">'1199.99'<\/span>), <span class=\"hljs-number\">20<\/span>, Decimal(<span class=\"hljs-string\">'0.24'<\/span>))\n(<span class=\"hljs-number\">2<\/span>, <span class=\"hljs-string\">'Galaxy S23 Ultra'<\/span>, Decimal(<span class=\"hljs-string\">'949.99'<\/span>), <span class=\"hljs-number\">9<\/span>, Decimal(<span class=\"hljs-string\">'0.23'<\/span>))\n(<span class=\"hljs-number\">3<\/span>, <span class=\"hljs-string\">'Pixel 7 Pro'<\/span>, Decimal(<span class=\"hljs-string\">'899.99'<\/span>), <span class=\"hljs-number\">8<\/span>, Decimal(<span class=\"hljs-string\">'0.21'<\/span>))\n(<span class=\"hljs-number\">4<\/span>, <span class=\"hljs-string\">'Xperia 1 IV'<\/span>, Decimal(<span class=\"hljs-string\">'1299.99'<\/span>), <span class=\"hljs-number\">7<\/span>, Decimal(<span class=\"hljs-string\">'0.19'<\/span>))<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id=\"how-it-works\" id='how-it-works'>How it works <a href=\"#how-it-works\" class=\"anchor\" id=\"how-it-works\" title=\"Anchor for How it works\">#<\/a><\/h2>\n\n\n\n<p><strong>Step 1: Import the&nbsp;<code>psycopg<\/code>&nbsp;library<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">import<\/span> psycopg<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The&nbsp;<code>psycopg<\/code>&nbsp;module allows Python to connect to PostgreSQL, execute SQL statements, and retrieve data.<\/p>\n\n\n\n<p><strong>Step 2: Import the database configuration<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">from<\/span> config <span class=\"hljs-keyword\">import<\/span> config<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This imports the database connection settings from&nbsp;<code>config.py<\/code>. For example:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-6\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">{\n    <span class=\"hljs-string\">\"host\"<\/span>: <span class=\"hljs-string\">\"localhost\"<\/span>,\n    <span class=\"hljs-string\">\"dbname\"<\/span>: <span class=\"hljs-string\">\"pyinventory\"<\/span>,\n    <span class=\"hljs-string\">\"user\"<\/span>: <span class=\"hljs-string\">\"postgres\"<\/span>,\n    <span class=\"hljs-string\">\"password\"<\/span>: <span class=\"hljs-string\">\"\"<\/span>\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><strong>Step 3: Define the SQL&nbsp;<code>SELECT<\/code>&nbsp;statement<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">sql = <span class=\"hljs-string\">\"\"\"\nSELECT product_id, name, price, safety_stock, gross_weight\nFROM products\nORDER BY product_id\n\"\"\"<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-7\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This <code>SELECT<\/code> statement:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Retrieves data in&nbsp;<code>product_id<\/code>,&nbsp;<code>name<\/code>,&nbsp;<code>price<\/code>,&nbsp;<code>safety_stock<\/code>, and&nbsp;<code>gross_weight<\/code>&nbsp;columns from the&nbsp;<code>products<\/code>&nbsp;table<\/li>\n\n\n\n<li>Sorts them by&nbsp;<code>product_id<\/code><\/li>\n<\/ul>\n\n\n\n<p><strong>Step 4: Open a database connection<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-8\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">with<\/span> psycopg.connect(**config) <span class=\"hljs-keyword\">as<\/span> conn:<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-8\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This creates a connection to PostgreSQL. The&nbsp;<code>with<\/code>&nbsp;statement automatically closes the connection when the block finishes.<\/p>\n\n\n\n<p><strong>Step 5: Create a cursor<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-9\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">with<\/span> conn.cursor() <span class=\"hljs-keyword\">as<\/span> cur:<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-9\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>We use a cursor to send an SQL <code>SELECT<\/code> statement to PostgreSQL and retrieve data.<\/p>\n\n\n\n<p><strong>Step 6: Execute the query<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-10\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">cur.execute(sql)<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-10\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The&nbsp;<code>execute()<\/code>&nbsp;method sends the&nbsp;<code>SELECT<\/code>&nbsp;statement to PostgreSQL and executes it.<\/p>\n\n\n\n<p>Since our SELECT statement has no parameters, you do not need to pass a second argument.<\/p>\n\n\n\n<p><strong>Step 7: Fetch all rows<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-11\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">rows = cur.fetchall()<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-11\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The&nbsp;<code>fetchall()<\/code>&nbsp;method returns all rows from the query result as a list of tuples.<\/p>\n\n\n\n<p><strong>Step 8: Process the rows<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-12\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">for<\/span> row <span class=\"hljs-keyword\">in<\/span> rows:\n    print(row)<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-12\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This loops through each row and displays it.<\/p>\n\n\n\n<p><strong>Step 9: Handle errors<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-13\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">except<\/span> Exception <span class=\"hljs-keyword\">as<\/span> e:\n    print(<span class=\"hljs-string\">f\"Error: <span class=\"hljs-subst\">{e}<\/span>\"<\/span>)<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-13\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>If an error occurs, Python prints the error message instead of crashing.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"select-one-row-by-id\" id='select-one-row-by-id'>Select one row by ID <a href=\"#select-one-row-by-id\" class=\"anchor\" id=\"select-one-row-by-id\" title=\"Anchor for Select one row by ID\">#<\/a><\/h2>\n\n\n\n<p>The following script selects one product by its&nbsp;<code>product_id<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-14\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">import<\/span> psycopg\n<span class=\"hljs-keyword\">from<\/span> config <span class=\"hljs-keyword\">import<\/span> config\n\nsql = <span class=\"hljs-string\">\"\"\"\nSELECT product_id, name, price, safety_stock, gross_weight\nFROM products\nWHERE product_id = %s\n\"\"\"<\/span>\n\nproduct_id = <span class=\"hljs-number\">1<\/span>\n\n<span class=\"hljs-keyword\">try<\/span>:\n    <span class=\"hljs-keyword\">with<\/span> psycopg.connect(**config) <span class=\"hljs-keyword\">as<\/span> conn:\n        <span class=\"hljs-keyword\">with<\/span> conn.cursor() <span class=\"hljs-keyword\">as<\/span> cur:\n            cur.execute(sql, (product_id,))\n            row = cur.fetchone()\n\n            <span class=\"hljs-keyword\">if<\/span> row:\n                print(<span class=\"hljs-string\">\"Product found:\"<\/span>)\n                print(row)\n            <span class=\"hljs-keyword\">else<\/span>:\n                print(<span class=\"hljs-string\">\"Product not found.\"<\/span>)\n<span class=\"hljs-keyword\">except<\/span> Exception <span class=\"hljs-keyword\">as<\/span> e:\n    print(<span class=\"hljs-string\">f\"Error: <span class=\"hljs-subst\">{e}<\/span>\"<\/span>)\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-14\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-15\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">Product found:\n(<span class=\"hljs-number\">1<\/span>, <span class=\"hljs-string\">'iPhone 14 Pro'<\/span>, Decimal(<span class=\"hljs-string\">'1199.99'<\/span>), <span class=\"hljs-number\">20<\/span>, Decimal(<span class=\"hljs-string\">'0.24'<\/span>))<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-15\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>How it works<\/p>\n\n\n\n<p><strong>Step 1. Define the SELECT statement<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-16\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">sql = <span class=\"hljs-string\">\"\"\"\nSELECT product_id, name, price, safety_stock, gross_weight\nFROM products\nWHERE product_id = %s\n\"\"\"<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-16\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This&nbsp;<code>SELECT<\/code>&nbsp;statement retrieves one row from the&nbsp;<code>products<\/code>&nbsp;table where&nbsp;<code>product_id<\/code>&nbsp;matches the provided value.<\/p>\n\n\n\n<p><strong>Step 2. Prepare the input value<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-17\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">product_id = <span class=\"hljs-number\">1<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-17\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This is the value that will be bound to the&nbsp;<code>%s<\/code>&nbsp;placeholder.<\/p>\n\n\n\n<p><strong>Step 3. Execute the query with a parameter<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-18\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">cur.execute(sql, (product_id,))<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-18\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The second argument is a tuple containing the parameter value.<\/p>\n\n\n\n<p>Note that&nbsp;<code>(product_id,)<\/code>&nbsp;includes a trailing comma, which makes it a tuple.<\/p>\n\n\n\n<p><strong>Step 4. Fetch one row<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-19\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">row = cur.fetchone()<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-19\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The&nbsp;<code>fetchone()<\/code>&nbsp;method returns the next row from the result set.<\/p>\n\n\n\n<p>If no row matches, the&nbsp;<code>fetchone()<\/code>&nbsp;returns&nbsp;<code>None<\/code>.<\/p>\n\n\n\n<p><strong>Step 5. Check the result<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-20\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">if<\/span> row:\n    print(<span class=\"hljs-string\">\"Product found:\"<\/span>)\n    print(row)\n<span class=\"hljs-keyword\">else<\/span>:\n    print(<span class=\"hljs-string\">\"Product not found.\"<\/span>)\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-20\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id=\"select-multiple-rows-with-a-condition\" id='select-multiple-rows-with-a-condition'>Select multiple rows with a condition <a href=\"#select-multiple-rows-with-a-condition\" class=\"anchor\" id=\"select-multiple-rows-with-a-condition\" title=\"Anchor for Select multiple rows with a condition\">#<\/a><\/h2>\n\n\n\n<p>The following script retrieves products whose price is greater than a given amount:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-21\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">import<\/span> psycopg\n<span class=\"hljs-keyword\">from<\/span> config <span class=\"hljs-keyword\">import<\/span> config\n\nsql = <span class=\"hljs-string\">\"\"\"\nSELECT product_id, name, price, safety_stock, gross_weight\nFROM products\nWHERE price &gt; %s\nORDER BY price DESC\n\"\"\"<\/span>\n\nmin_price = <span class=\"hljs-number\">900<\/span>\n\n<span class=\"hljs-keyword\">try<\/span>:\n    <span class=\"hljs-keyword\">with<\/span> psycopg.connect(**config) <span class=\"hljs-keyword\">as<\/span> conn:\n        <span class=\"hljs-keyword\">with<\/span> conn.cursor() <span class=\"hljs-keyword\">as<\/span> cur:\n            cur.execute(sql, (min_price,))\n            rows = cur.fetchall()\n\n            print(<span class=\"hljs-string\">\"Matching products:\"<\/span>)\n            <span class=\"hljs-keyword\">for<\/span> row <span class=\"hljs-keyword\">in<\/span> rows:\n                print(row)\n<span class=\"hljs-keyword\">except<\/span> Exception <span class=\"hljs-keyword\">as<\/span> e:\n    print(<span class=\"hljs-string\">f\"Error: <span class=\"hljs-subst\">{e}<\/span>\"<\/span>)\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-21\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-22\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">Matching products:\n(<span class=\"hljs-number\">4<\/span>, <span class=\"hljs-string\">'Xperia 1 IV'<\/span>, Decimal(<span class=\"hljs-string\">'1299.99'<\/span>), <span class=\"hljs-number\">7<\/span>, Decimal(<span class=\"hljs-string\">'0.19'<\/span>))\n(<span class=\"hljs-number\">1<\/span>, <span class=\"hljs-string\">'iPhone 14 Pro'<\/span>, Decimal(<span class=\"hljs-string\">'1199.99'<\/span>), <span class=\"hljs-number\">20<\/span>, Decimal(<span class=\"hljs-string\">'0.24'<\/span>))\n(<span class=\"hljs-number\">2<\/span>, <span class=\"hljs-string\">'Galaxy S23 Ultra'<\/span>, Decimal(<span class=\"hljs-string\">'949.99'<\/span>), <span class=\"hljs-number\">9<\/span>, Decimal(<span class=\"hljs-string\">'0.23'<\/span>))<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-22\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>How it works<\/p>\n\n\n\n<p><strong>Step 1. Define the SELECT statement<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-23\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">sql = <span class=\"hljs-string\">\"\"\"\nSELECT product_id, name, price, safety_stock, gross_weight\nFROM products\nWHERE price &gt; %s\nORDER BY price DESC\n\"\"\"<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-23\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This <code>SELECT<\/code> statement:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Filters rows using&nbsp;<code>WHERE price &gt; %s<\/code><\/li>\n\n\n\n<li>Sorts matching rows by price in descending order<\/li>\n<\/ul>\n\n\n\n<p><strong>Step 2. Prepare the parameter<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-24\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">min_price = <span class=\"hljs-number\">900<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-24\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This value will be passed safely into the query.<\/p>\n\n\n\n<p><strong>Step 3. Execute the query<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-25\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">cur.execute(sql, (min_price,))<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-25\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Psycopg replaces&nbsp;<code>%s<\/code>&nbsp;with the provided value safely.<\/p>\n\n\n\n<p><strong>Step 4. Fetch all matching rows<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-26\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">rows = cur.fetchall()<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-26\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The <code>fetchall()<\/code> returns all rows that match the condition.<\/p>\n\n\n\n<p><strong>Step 5. Print the results<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-27\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">print(<span class=\"hljs-string\">\"Matching products:\"<\/span>)\n<span class=\"hljs-keyword\">for<\/span> row <span class=\"hljs-keyword\">in<\/span> rows:\n    print(row)\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-27\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This code loops through the result and displays each row.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"select-a-limited-number-of-rows-with-fetchmany\" id='select-a-limited-number-of-rows-withfetchmany'>Select a limited number of rows with&nbsp;fetchmany() <a href=\"#select-a-limited-number-of-rows-withfetchmany\" class=\"anchor\" id=\"select-a-limited-number-of-rows-withfetchmany\" title=\"Anchor for Select a limited number of rows with&nbsp;&lt;code&gt;fetchmany()&lt;\/code&gt;\">#<\/a><\/h2>\n\n\n\n<p>Sometimes, you may not want to load all rows at once. In these cases, you can use&nbsp;<code>fetchmany()<\/code>&nbsp;to retrieve a limited number of rows.<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-28\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">import<\/span> psycopg\n<span class=\"hljs-keyword\">from<\/span> config <span class=\"hljs-keyword\">import<\/span> config\n\nsql = <span class=\"hljs-string\">\"\"\"\nSELECT product_id, name, price, safety_stock, gross_weight\nFROM products\nORDER BY product_id\n\"\"\"<\/span>\n\n<span class=\"hljs-keyword\">try<\/span>:\n    <span class=\"hljs-keyword\">with<\/span> psycopg.connect(**config) <span class=\"hljs-keyword\">as<\/span> conn:\n        <span class=\"hljs-keyword\">with<\/span> conn.cursor() <span class=\"hljs-keyword\">as<\/span> cur:\n            cur.execute(sql)\n            rows = cur.fetchmany(<span class=\"hljs-number\">2<\/span>)\n\n            print(<span class=\"hljs-string\">\"First 2 rows:\"<\/span>)\n            <span class=\"hljs-keyword\">for<\/span> row <span class=\"hljs-keyword\">in<\/span> rows:\n                print(row)\n<span class=\"hljs-keyword\">except<\/span> Exception <span class=\"hljs-keyword\">as<\/span> e:\n    print(<span class=\"hljs-string\">f\"Error: <span class=\"hljs-subst\">{e}<\/span>\"<\/span>)\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-28\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-29\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">First <span class=\"hljs-number\">2<\/span> rows:\n(<span class=\"hljs-number\">1<\/span>, <span class=\"hljs-string\">'iPhone 14 Pro'<\/span>, Decimal(<span class=\"hljs-string\">'999.99'<\/span>), <span class=\"hljs-number\">10<\/span>, Decimal(<span class=\"hljs-string\">'0.24'<\/span>))\n(<span class=\"hljs-number\">2<\/span>, <span class=\"hljs-string\">'Galaxy S23 Ultra'<\/span>, Decimal(<span class=\"hljs-string\">'1199.99'<\/span>), <span class=\"hljs-number\">15<\/span>, Decimal(<span class=\"hljs-string\">'0.23'<\/span>))\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-29\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>How it works<\/p>\n\n\n\n<p><strong>Step 1. Execute the query<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-30\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">cur.execute(sql)<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-30\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><strong>Step 2. Fetch a fixed number of rows<\/strong><\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-31\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">rows = cur.fetchmany(<span class=\"hljs-number\">2<\/span>)<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-31\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The&nbsp;<code>fetchmany(2)<\/code>&nbsp;retrieves up to 2 rows from the result set.<\/p>\n\n\n\n<p>The <code>fetchmany<\/code> can be useful when you want to process rows in smaller batches and do not want to load everything into memory at once.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"select-specific-columns-only\" id='select-specific-columns-only'>Select specific columns only <a href=\"#select-specific-columns-only\" class=\"anchor\" id=\"select-specific-columns-only\" title=\"Anchor for Select specific columns only\">#<\/a><\/h2>\n\n\n\n<p>In practice, you do not always need every column in a table. For example, this script retrieves only the product name and price:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-32\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\"><span class=\"hljs-keyword\">import<\/span> psycopg\n<span class=\"hljs-keyword\">from<\/span> config <span class=\"hljs-keyword\">import<\/span> config\n\nsql = <span class=\"hljs-string\">\"\"\"\nSELECT name, price\nFROM products\nORDER BY name\n\"\"\"<\/span>\n\n<span class=\"hljs-keyword\">try<\/span>:\n    <span class=\"hljs-keyword\">with<\/span> psycopg.connect(**config) <span class=\"hljs-keyword\">as<\/span> conn:\n        <span class=\"hljs-keyword\">with<\/span> conn.cursor() <span class=\"hljs-keyword\">as<\/span> cur:\n            cur.execute(sql)\n            rows = cur.fetchall()\n\n            <span class=\"hljs-keyword\">for<\/span> row <span class=\"hljs-keyword\">in<\/span> rows:\n                print(row)\n<span class=\"hljs-keyword\">except<\/span> Exception <span class=\"hljs-keyword\">as<\/span> e:\n    print(<span class=\"hljs-string\">f\"Error: <span class=\"hljs-subst\">{e}<\/span>\"<\/span>)\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-32\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Example output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-33\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">(<span class=\"hljs-string\">'Galaxy S23 Ultra'<\/span>, Decimal(<span class=\"hljs-string\">'949.99'<\/span>))\n(<span class=\"hljs-string\">'iPhone 14 Pro'<\/span>, Decimal(<span class=\"hljs-string\">'1199.99'<\/span>))\n(<span class=\"hljs-string\">'Pixel 7 Pro'<\/span>, Decimal(<span class=\"hljs-string\">'899.99'<\/span>))\n(<span class=\"hljs-string\">'Xperia 1 IV'<\/span>, Decimal(<span class=\"hljs-string\">'1299.99'<\/span>))<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-33\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>This can make the program run faster when you only need a few columns.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"why-use-parameterized-queries\" id='why-use-parameterized-queries'>Why use parameterized queries <a href=\"#why-use-parameterized-queries\" class=\"anchor\" id=\"why-use-parameterized-queries\" title=\"Anchor for Why use parameterized queries\">#<\/a><\/h2>\n\n\n\n<p>When retrieving data with conditions, you should always use placeholders like&nbsp;<code>%s<\/code>&nbsp;instead of building SQL strings manually.<\/p>\n\n\n\n<p>Good:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-34\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">sql = <span class=\"hljs-string\">\"SELECT * FROM products WHERE product_id = %s\"<\/span>\ncur.execute(sql, (<span class=\"hljs-number\">1<\/span>,))<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-34\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Avoid:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-35\" data-shcb-language-name=\"Python\" data-shcb-language-slug=\"python\"><span><code class=\"hljs language-python\">sql = <span class=\"hljs-string\">f\"SELECT * FROM products WHERE product_id = <span class=\"hljs-subst\">{product_id}<\/span>\"<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-35\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Python<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">python<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Parameterized queries are better because they help prevent SQL injection, let Psycopg convert Python values safely, and keep your code cleaner and easier to maintain.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"summary\" id='summary'>Summary <a href=\"#summary\" class=\"anchor\" id=\"summary\" title=\"Anchor for Summary\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Use\u00a0<code>psycopg.connect()<\/code>\u00a0to open a connection to PostgreSQL.<\/li>\n\n\n\n<li>Use\u00a0<code>execute()<\/code>\u00a0to execute a query.<\/li>\n\n\n\n<li>Use&nbsp;<code>%s<\/code>&nbsp;placeholders and pass values separately for safe filtering.<\/li>\n\n\n\n<li>Use\u00a0<code>fetchone()<\/code>\u00a0to retrieve one row.<\/li>\n\n\n\n<li>Use\u00a0<code>fetchall()<\/code>\u00a0to retrieve all matching rows.<\/li>\n\n\n\n<li>Use\u00a0<code>fetchmany()<\/code>\u00a0to retrieve a limited number of rows.<\/li>\n\n\n\n<li>Use&nbsp;<code>with<\/code>&nbsp;blocks to manage connections and cursors automatically.<\/li>\n\n\n\n<li>Use&nbsp;<code>try\/except<\/code>&nbsp;to catch errors and make debugging easier.<\/li>\n<\/ul>\n<div class=\"helpful-block-content\" data-title=\"\">\n\t<header>\n\t\t<div class=\"wth-question\">Was this tutorial helpful ?<\/div>\n\t\t<div 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Here are the steps for retrieving data from a table in PostgreSQL from Python: Prerequisites # This tutorial assumes you already have a&nbsp;products&nbsp;table like this in the&nbsp;pyinventory&nbsp;database: It also assumes that the table already contains [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2630,"menu_order":4,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2667","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>PostgreSQL Python: Select Data from a Table with psycopg3<\/title>\n<meta name=\"description\" content=\"In this tutorial, you&#039;ll learn how to select one or multiple rows and filter rows from a table using\u00a0Psycopg 3.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" 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