{"id":1427,"date":"2025-01-04T19:14:01","date_gmt":"2025-01-04T12:14:01","guid":{"rendered":"https:\/\/www.pgtutorial.com\/?page_id=1427"},"modified":"2025-01-06T16:43:17","modified_gmt":"2025-01-06T09:43:17","slug":"plpgsql-blocks","status":"publish","type":"page","link":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/","title":{"rendered":"PL\/pgSQL Blocks"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you&#8217;ll learn about PL\/pgSQL blocks, how to create and execute some blocks.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='overview-of-a-plpgsql-block'>Overview of a PL\/pgSQL Block <a href=\"#overview-of-a-plpgsql-block\" class=\"anchor\" id=\"overview-of-a-plpgsql-block\" title=\"Anchor for Overview of a PL\/pgSQL Block\">#<\/a><\/h2>\n\n\n\n<p>PL\/pgSQL is a blocked structure programming language. PL\/pgSQL organizes code into blocks.<\/p>\n\n\n\n<p>Here&#8217;s the syntax of a block:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\">&#91; <span class=\"hljs-symbol\">&lt;&lt;label&gt;&gt;<\/span> ]\n&#91; <span class=\"hljs-keyword\">DECLARE<\/span>\n    declarations ]\n<span class=\"hljs-keyword\">BEGIN<\/span>\n    statements\n<span class=\"hljs-keyword\">END<\/span> &#91; label ];<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>A block has two main sections:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Declaration:<\/strong> The declaration section is optional. It is where you declare variables, constants, and cursors.<\/li>\n\n\n\n<li><strong>Body:<\/strong> The body section is required. It is where you put the logic of the block, such as SQL statements.<\/li>\n<\/ul>\n\n\n\n<p>A block may include an optional label appearing at the beginning and end. The label is necessary only when you use statements like the <code>EXIT<\/code> statement or to qualify the variable names declared in the block.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='plpgsql-block-example'>PL\/pgSQL Block Example <a href=\"#plpgsql-block-example\" class=\"anchor\" id=\"plpgsql-block-example\" title=\"Anchor for PL\/pgSQL Block Example\">#<\/a><\/h2>\n\n\n\n<p>The following example shows how to create a block that displays a message <code>\"Hello, World\"<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">DO<\/span>\n$$<span class=\"pgsql\">\n<span class=\"hljs-keyword\">BEGIN<\/span>\n    <span class=\"hljs-keyword\">RAISE<\/span> <span class=\"hljs-keyword\">NOTICE<\/span> <span class=\"hljs-string\">'%'<\/span>, <span class=\"hljs-string\">'Hello, World'<\/span>;\n<span class=\"hljs-keyword\">END<\/span>;\n$$<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/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-3\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">NOTICE<\/span>:  Hello, World<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>How it works:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>The <code>DO<\/code> statement executes the PL\/pgSQL block.<\/li>\n\n\n\n<li>We use the PL\/pgSQL block as a dollar-quoted string constant, which starts with <code>$$<\/code> and ends with <code>$$<\/code>. This helps avoid escaping quotations and special characters in the PL\/pgSQL code.<\/li>\n\n\n\n<li>A block starts with the <code>BEGIN<\/code> keyword and ends with the keyword <code>END<\/code>. Note that <code>BEGIN<\/code> doesn&#8217;t mean start a transaction.<\/li>\n<\/ol>\n\n\n\n<p>The <code>RAISE NOTICE<\/code> statement displays a notice when you execute the block:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">RAISE<\/span> <span class=\"hljs-keyword\">NOTICE<\/span> <span class=\"hljs-string\">'%'<\/span>, <span class=\"hljs-string\">'Hello, World'<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The <code>RAISE NOTICE<\/code> statement starts with a placeholder <code>%<\/code>, followed by a comma, and the value for that placeholder. The block does not include a declaration section in this example.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='executing-the-block-in-psql'>Executing the Block in psql <a href=\"#executing-the-block-in-psql\" class=\"anchor\" id=\"executing-the-block-in-psql\" title=\"Anchor for Executing the Block in psql\">#<\/a><\/h2>\n\n\n\n<p>First, connect to PostgreSQL using the psql tool:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\">psql -U postgres<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The psql tool will prompt you to enter the password for the postgres user:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-6\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">Password<\/span> <span class=\"hljs-keyword\">for<\/span> <span class=\"hljs-keyword\">user<\/span> postgres:<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>You must enter a valid password and press the Enter (or Return) key.<\/p>\n\n\n\n<p>Second, copy the PL\/pgSQL code above and paste it into the psql tool:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\">postgres=# <span class=\"hljs-keyword\">DO<\/span>\npostgres-# $$<span class=\"ruby\">\npostgres$# <span class=\"hljs-keyword\">BEGIN<\/span>\npostgres$#     RAISE NOTICE <span class=\"hljs-string\">'%'<\/span>, <span class=\"hljs-string\">'Hello, World'<\/span>;\npostgres$# <span class=\"hljs-keyword\">END<\/span>;\npostgres$# $$<\/span>;\n<span class=\"hljs-keyword\">NOTICE<\/span>:  Hello, World\n<span class=\"hljs-keyword\">DO<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-7\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/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-8\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">NOTICE<\/span>:  Hello, World\n<span class=\"hljs-keyword\">DO<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-8\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='executing-the-plpgsql-block-using-pgadmin-4'>Executing the PL\/pgSQL Block Using pgAdmin 4 <a href=\"#executing-the-plpgsql-block-using-pgadmin-4\" class=\"anchor\" id=\"executing-the-plpgsql-block-using-pgadmin-4\" title=\"Anchor for Executing the PL\/pgSQL Block Using pgAdmin 4\">#<\/a><\/h2>\n\n\n\n<p>First, launch the pgAdmin4 tool and open the inventory database.<\/p>\n\n\n\n<p>Second, open the query tool by following the menu path <strong>Tools &gt; Query tool<\/strong>:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"346\" height=\"177\" src=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/Query-Tool.png\" alt=\"Query Tool\" class=\"wp-image-1429\" srcset=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/Query-Tool.png 346w, https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/Query-Tool-300x153.png 300w\" sizes=\"auto, (max-width: 346px) 100vw, 346px\" \/><\/figure>\n\n\n\n<p>Third, copy and paste the PL\/pgSQL block into the query tool:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"452\" height=\"352\" src=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/plpgsql-block.png\" alt=\"Execute a PL\/pgSQL block\" class=\"wp-image-1430\" srcset=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/plpgsql-block.png 452w, https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/plpgsql-block-300x234.png 300w\" sizes=\"auto, (max-width: 452px) 100vw, 452px\" \/><\/figure>\n\n\n\n<p>Finally, click the <strong>Execute Script<\/strong> button (or press the <code>F5<\/code> keyboard shortcut).<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='plpgsql-block-with-declaration-example'>PL\/pgSQL Block with Declaration Example <a href=\"#plpgsql-block-with-declaration-example\" class=\"anchor\" id=\"plpgsql-block-with-declaration-example\" title=\"Anchor for PL\/pgSQL Block with Declaration Example\">#<\/a><\/h2>\n\n\n\n<p>The following example shows how to define a block with a declaration section.<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-9\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">DO<\/span>\n$$<span class=\"pgsql\">\n<span class=\"hljs-keyword\">DECLARE<\/span>\n    <span class=\"hljs-type\">name<\/span> <span class=\"hljs-type\">VARCHAR<\/span> = <span class=\"hljs-string\">'Joe'<\/span>;\n<span class=\"hljs-keyword\">BEGIN<\/span>\n    <span class=\"hljs-keyword\">RAISE<\/span> <span class=\"hljs-keyword\">NOTICE<\/span> <span class=\"hljs-string\">'Hello %'<\/span>, <span class=\"hljs-type\">name<\/span>;\n<span class=\"hljs-keyword\">END<\/span>;\n$$<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-9\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/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-10\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">NOTICE<\/span>:  Hello Joe<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-10\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In this example, we add the declaration section and declare a variable <code>name<\/code> with <code><a href=\"https:\/\/www.pgtutorial.com\/postgresql-tutorial\/postgresql-varchar\/\">VARCHAR<\/a><\/code> type and value <code>'Joe'<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-11\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">DECLARE<\/span>\n    <span class=\"hljs-type\">name<\/span> <span class=\"hljs-type\">VARCHAR<\/span> = <span class=\"hljs-string\">'Joe'<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-11\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>To declare a variable, you provide the name, data type, and initial value:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-12\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-type\">name<\/span> <span class=\"hljs-type\">VARCHAR<\/span> = <span class=\"hljs-string\">'Joe'<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-12\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>We substitute the <code>name<\/code> variable with the placeholder <code>%<\/code> in the <code>'Hello %'<\/code> string in the <code>RAISE NOTICE<\/code> statement:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-13\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">RAISE<\/span> <span class=\"hljs-keyword\">NOTICE<\/span> <span class=\"hljs-string\">'Hello %'<\/span>, <span class=\"hljs-type\">name<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-13\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The output will be like this:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-14\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">NOTICE<\/span>:  Hello Joe<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-14\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='plpgsql-subblocks'>PL\/pgSQL Subblocks <a href=\"#plpgsql-subblocks\" class=\"anchor\" id=\"plpgsql-subblocks\" title=\"Anchor for PL\/pgSQL Subblocks\">#<\/a><\/h2>\n\n\n\n<p>In PL\/pgSQL, blocks can be nested within the body of other blocks. Blocks nested inside other blocks are called subblocks. Blocks that contain nested blocks are called outer blocks:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"400\" height=\"290\" src=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/PLPGSQL-Block-Structure.png\" alt=\"PL\/pgSQL Block Structure\" class=\"wp-image-1439\" srcset=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/PLPGSQL-Block-Structure.png 400w, https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/PLPGSQL-Block-Structure-300x218.png 300w\" sizes=\"auto, (max-width: 400px) 100vw, 400px\" \/><\/figure>\n\n\n\n<p>Block nesting allows you to organize the blocks into smaller, more manageable trunks. For example:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-15\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">DO<\/span>\n$$<span class=\"pgsql\">\n<span class=\"hljs-keyword\">DECLARE<\/span>\n    total_quantity <span class=\"hljs-type\">INT<\/span> = <span class=\"hljs-number\">0<\/span>;\n<span class=\"hljs-keyword\">BEGIN<\/span>\n     <span class=\"hljs-keyword\">DECLARE<\/span>\n          safety_stock <span class=\"hljs-type\">INT<\/span> = <span class=\"hljs-number\">10<\/span>;\n          on_hand_qty <span class=\"hljs-type\">INT<\/span> = <span class=\"hljs-number\">100<\/span>;\n     <span class=\"hljs-keyword\">BEGIN<\/span>\n          total_quantity = safety_stock + on_hand_qty;\n     <span class=\"hljs-keyword\">END<\/span>;\n     <span class=\"hljs-keyword\">RAISE<\/span> <span class=\"hljs-keyword\">NOTICE<\/span> <span class=\"hljs-string\">'The total quantity is %'<\/span>, total_quantity;\n<span class=\"hljs-keyword\">END<\/span>;\n$$<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-15\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/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-16\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">NOTICE<\/span>:  The total quantity <span class=\"hljs-keyword\">is<\/span> <span class=\"hljs-number\">110<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-16\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>How it works:<\/p>\n\n\n\n<p>In the main block, we declare and initialize <code>total_quantity<\/code> to 0:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-17\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">DECLARE<\/span>\n    total_quantity <span class=\"hljs-type\">INT<\/span> = <span class=\"hljs-number\">0<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-17\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In the subblock, we declare and initialize <code>safety_stock<\/code> to 10 and <code>on_hand_qty<\/code> to 100:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-18\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">DECLARE<\/span>\n    safety_stock <span class=\"hljs-type\">INT<\/span> = <span class=\"hljs-number\">10<\/span>;\n    on_hand_qty <span class=\"hljs-type\">INT<\/span> = <span class=\"hljs-number\">100<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-18\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Additionally, we calculate the total quantity by adding <code>safety_stock<\/code> and <code>on_hand_qty<\/code> and assigning the result to <code>total_quantity<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-19\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\">total_quantity = safety_stock + on_hand_qty;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-19\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>After the subblock, we display the total quantity in the main block:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-20\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">RAISE<\/span> <span class=\"hljs-keyword\">NOTICE<\/span> <span class=\"hljs-string\">'The total quantity is %'<\/span>, total_quantity;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-20\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" 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>PL\/pgSQL is a blocked structure programming language.<\/li>\n\n\n\n<li>A block includes two main sections: declaration and body.<\/li>\n\n\n\n<li>The declaration section is optional, while the body section is required.<\/li>\n\n\n\n<li>Blocks can be nested within the body section of other blocks.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id='quiz'>Quiz <a href=\"#quiz\" class=\"anchor\" id=\"quiz\" title=\"Anchor for Quiz\">#<\/a><\/h2>\n\n\n\n<iframe loading=\"lazy\"\n  name=\"quiz\"\n  src=\"\/quiz\/?quiz=plpgsql-block\"\n  height=\"700\"\n  width=\"600\"\n  class=\"iframe\"\n><\/iframe>\n\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 class=\"wth-thumbs\">\n\t\t\t<button\n\t\t\t\tdata-post=\"1427\"\n\t\t\t\tdata-post-url=\"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/\"\n\t\t\t\tdata-post-title=\"PL\/pgSQL Blocks\"\n\t\t\t\tdata-response=\"1\"\n\t\t\t\tclass=\"wth-btn-rounded wth-yes-btn\"\n\t\t\t>\n\t\t\t\t<svg\n\t\t\t\t\txmlns=\"http:\/\/www.w3.org\/2000\/svg\"\n\t\t\t\t\tviewBox=\"0 0 24 24\"\n\t\t\t\t\tfill=\"none\"\n\t\t\t\t\tstroke=\"currentColor\"\n\t\t\t\t\tstroke-width=\"2\"\n\t\t\t\t\tstroke-linecap=\"round\"\n\t\t\t\t\tstroke-linejoin=\"round\"\n\t\t\t\t\tclass=\"feather feather-thumbs-up block w-full h-full\"\n\t\t\t\t>\n\t\t\t\t\t<path\n\t\t\t\t\t\td=\"M14 9V5a3 3 0 0 0-3-3l-4 9v11h11.28a2 2 0 0 0 2-1.7l1.38-9a2 2 0 0 0-2-2.3zM7 22H4a2 2 0 0 1-2-2v-7a2 2 0 0 1 2-2h3\"\n\t\t\t\t\t><\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t<span class=\"sr-only\"> Yes <\/span>\n\t\t\t<\/button>\n\n\t\t\t<button\n\t\t\t\tdata-response=\"0\"\n\t\t\t\tdata-post=\"1427\"\n\t\t\t\tdata-post-url=\"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/\"\n\t\t\t\tdata-post-title=\"PL\/pgSQL Blocks\"\n\t\t\t\tclass=\"wth-btn-rounded wth-no-btn\"\n\t\t\t>\n\t\t\t\t<svg\n\t\t\t\t\txmlns=\"http:\/\/www.w3.org\/2000\/svg\"\n\t\t\t\t\tviewBox=\"0 0 24 24\"\n\t\t\t\t\tfill=\"none\"\n\t\t\t\t\tstroke=\"currentColor\"\n\t\t\t\t\tstroke-width=\"2\"\n\t\t\t\t\tstroke-linecap=\"round\"\n\t\t\t\t\tstroke-linejoin=\"round\"\n\t\t\t\t>\n\t\t\t\t\t<path\n\t\t\t\t\t\td=\"M10 15v4a3 3 0 0 0 3 3l4-9V2H5.72a2 2 0 0 0-2 1.7l-1.38 9a2 2 0 0 0 2 2.3zm7-13h2.67A2.31 2.31 0 0 1 22 4v7a2.31 2.31 0 0 1-2.33 2H17\"\n\t\t\t\t\t><\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t<span class=\"sr-only\"> No <\/span>\n\t\t\t<\/button>\n\t\t<\/div>\n\t<\/header>\n\n\t<div class=\"wth-form hidden\">\n\t\t<div class=\"wth-form-wrapper\">\n\t\t\t<div class=\"wth-title\"><\/div>\n\t\t\t\n\t\t\t<textarea class=\"wth-message\"><\/textarea>\n\n\t\t\t<button class=\"btn btn-primary wth-btn-submit\">Send<\/button>\n\t\t\t<button class=\"btn wth-btn-cancel\">Cancel<\/button>\n\t\t\n\t\t<\/div>\n\t<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Summary: in this tutorial, you&#8217;ll learn about PL\/pgSQL blocks, how to create and execute some blocks. Overview of a PL\/pgSQL Block # PL\/pgSQL is a blocked structure programming language. PL\/pgSQL organizes code into blocks. Here&#8217;s the syntax of a block: A block has two main sections: A block may include an optional label appearing at [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1420,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1427","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>PL\/pgSQL Blocks<\/title>\n<meta name=\"description\" content=\"In this tutorial, you&#039;ll learn about PL\/pgSQL blocks and how to create and execute some blocks.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"PL\/pgSQL Blocks\" \/>\n<meta property=\"og:description\" content=\"In this tutorial, you&#039;ll learn about PL\/pgSQL blocks and how to create and execute some blocks.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/\" \/>\n<meta property=\"og:site_name\" content=\"PostgreSQL Tutorial\" \/>\n<meta property=\"article:modified_time\" content=\"2025-01-06T09:43:17+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/Query-Tool.png\" \/>\n\t<meta property=\"og:image:width\" content=\"346\" \/>\n\t<meta property=\"og:image:height\" content=\"177\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"3 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.pgtutorial.com\\\/plpgsql\\\/plpgsql-blocks\\\/\",\"url\":\"https:\\\/\\\/www.pgtutorial.com\\\/plpgsql\\\/plpgsql-blocks\\\/\",\"name\":\"PL\\\/pgSQL Blocks\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.pgtutorial.com\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/www.pgtutorial.com\\\/plpgsql\\\/plpgsql-blocks\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/www.pgtutorial.com\\\/plpgsql\\\/plpgsql-blocks\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.pgtutorial.com\\\/wp-content\\\/uploads\\\/2025\\\/01\\\/Query-Tool.png\",\"datePublished\":\"2025-01-04T12:14:01+00:00\",\"dateModified\":\"2025-01-06T09:43:17+00:00\",\"description\":\"In this tutorial, you'll learn about PL\\\/pgSQL blocks and how to create and execute some blocks.\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.pgtutorial.com\\\/plpgsql\\\/plpgsql-blocks\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.pgtutorial.com\\\/plpgsql\\\/plpgsql-blocks\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.pgtutorial.com\\\/plpgsql\\\/plpgsql-blocks\\\/#primaryimage\",\"url\":\"https:\\\/\\\/www.pgtutorial.com\\\/wp-content\\\/uploads\\\/2025\\\/01\\\/Query-Tool.png\",\"contentUrl\":\"https:\\\/\\\/www.pgtutorial.com\\\/wp-content\\\/uploads\\\/2025\\\/01\\\/Query-Tool.png\",\"width\":346,\"height\":177,\"caption\":\"Query Tool\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.pgtutorial.com\\\/plpgsql\\\/plpgsql-blocks\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/www.pgtutorial.com\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"PL\\\/pgSQL\",\"item\":\"https:\\\/\\\/www.pgtutorial.com\\\/plpgsql\\\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"PL\\\/pgSQL Blocks\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.pgtutorial.com\\\/#website\",\"url\":\"https:\\\/\\\/www.pgtutorial.com\\\/\",\"name\":\"PostgreSQL Tutorial\",\"description\":\"Learn PostgreSQL from Scratch\",\"alternateName\":\"PostgreSQL\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/www.pgtutorial.com\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"PL\/pgSQL Blocks","description":"In this tutorial, you'll learn about PL\/pgSQL blocks and how to create and execute some blocks.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/","og_locale":"en_US","og_type":"article","og_title":"PL\/pgSQL Blocks","og_description":"In this tutorial, you'll learn about PL\/pgSQL blocks and how to create and execute some blocks.","og_url":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/","og_site_name":"PostgreSQL Tutorial","article_modified_time":"2025-01-06T09:43:17+00:00","og_image":[{"width":346,"height":177,"url":"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/Query-Tool.png","type":"image\/png"}],"twitter_card":"summary_large_image","twitter_misc":{"Est. reading time":"3 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/","url":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/","name":"PL\/pgSQL Blocks","isPartOf":{"@id":"https:\/\/www.pgtutorial.com\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/#primaryimage"},"image":{"@id":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/#primaryimage"},"thumbnailUrl":"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/Query-Tool.png","datePublished":"2025-01-04T12:14:01+00:00","dateModified":"2025-01-06T09:43:17+00:00","description":"In this tutorial, you'll learn about PL\/pgSQL blocks and how to create and execute some blocks.","breadcrumb":{"@id":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/#primaryimage","url":"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/Query-Tool.png","contentUrl":"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2025\/01\/Query-Tool.png","width":346,"height":177,"caption":"Query Tool"},{"@type":"BreadcrumbList","@id":"https:\/\/www.pgtutorial.com\/plpgsql\/plpgsql-blocks\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.pgtutorial.com\/"},{"@type":"ListItem","position":2,"name":"PL\/pgSQL","item":"https:\/\/www.pgtutorial.com\/plpgsql\/"},{"@type":"ListItem","position":3,"name":"PL\/pgSQL Blocks"}]},{"@type":"WebSite","@id":"https:\/\/www.pgtutorial.com\/#website","url":"https:\/\/www.pgtutorial.com\/","name":"PostgreSQL Tutorial","description":"Learn PostgreSQL from Scratch","alternateName":"PostgreSQL","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.pgtutorial.com\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"}]}},"_links":{"self":[{"href":"https:\/\/www.pgtutorial.com\/wp-json\/wp\/v2\/pages\/1427","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.pgtutorial.com\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.pgtutorial.com\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.pgtutorial.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.pgtutorial.com\/wp-json\/wp\/v2\/comments?post=1427"}],"version-history":[{"count":8,"href":"https:\/\/www.pgtutorial.com\/wp-json\/wp\/v2\/pages\/1427\/revisions"}],"predecessor-version":[{"id":1522,"href":"https:\/\/www.pgtutorial.com\/wp-json\/wp\/v2\/pages\/1427\/revisions\/1522"}],"up":[{"embeddable":true,"href":"https:\/\/www.pgtutorial.com\/wp-json\/wp\/v2\/pages\/1420"}],"wp:attachment":[{"href":"https:\/\/www.pgtutorial.com\/wp-json\/wp\/v2\/media?parent=1427"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}