{"id":4264,"date":"2024-07-26T13:53:18","date_gmt":"2024-07-26T06:53:18","guid":{"rendered":"https:\/\/www.sqlservertutorial.net\/?page_id=4264"},"modified":"2024-07-29T07:52:03","modified_gmt":"2024-07-29T00:52:03","slug":"java-sql-server-select","status":"publish","type":"page","link":"https:\/\/www.sqlservertutorial.net\/java-sql-server\/java-sql-server-select\/","title":{"rendered":"Java SQL Server: Selecting Data"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you will learn how to query data from a table in SQL Server using JDBC API.<\/p>\n\n\n\n<p class=\"note\">This tutorial begins where&nbsp;the&nbsp;<a href=\"https:\/\/www.sqlservertutorial.net\/java-sql-server\/java-sql-server-batch-processing\/\">Performing Batch Operations in Java tutorial<\/a>&nbsp;left off.<\/p>\n\n\n\n<p>The following are the steps for querying data from a table in SQL Server using JDBC:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>First,&nbsp;<a href=\"https:\/\/www.sqlservertutorial.net\/java-sql-server\/java-connect-to-sql-server\/\">connect to the SQL Server database<\/a>.<\/li>\n\n\n\n<li>Second, create a new&nbsp;<code>PreparedStatement<\/code>&nbsp;object (or&nbsp;<code>Statement<\/code>&nbsp;object) with a&nbsp;<code>SELECT<\/code>&nbsp;statement.<\/li>\n\n\n\n<li>Third, set the values for the parameters of the statement by calling the&nbsp;<code>set*<\/code>&nbsp;methods of the&nbsp;<code>PreparedStatement<\/code>&nbsp;object.<\/li>\n\n\n\n<li>Fourth, execute the <code>SELECT<\/code> statement in SQL Server by calling the&nbsp;<code>executeQuery()<\/code>&nbsp;method of the <code>Statement<\/code> object. The&nbsp;method returns a&nbsp;<code>ResultSet<\/code>&nbsp;object.<\/li>\n\n\n\n<li>Fifth, iterate over the rows from the <code>ResultSet<\/code> by calling its&nbsp;<code>next()<\/code>&nbsp;method and process each row individually.<\/li>\n\n\n\n<li>Finally, close the result set, statement, and database connection. If you use the try-with-resources, you don&#8217;t need to close them manually.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id='selecting-all-rows-from-a-table'>Selecting all rows from a table <a href=\"#selecting-all-rows-from-a-table\" class=\"anchor\" id=\"selecting-all-rows-from-a-table\" title=\"Anchor for Selecting all rows from a table\">#<\/a><\/h2>\n\n\n\n<p>We&#8217;ll show you how to query all rows from the <code>Authors<\/code> table and return a list of <code>Author<\/code> objects:<\/p>\n\n\n\n<p>Step 1. Modify the <code>AuthorDB<\/code> class by adding the <code>findAll()<\/code> method that returns all rows from the <code>Authors<\/code> table as a list of <code>Author<\/code> objects:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">public<\/span> List &lt; Author &gt; findAll() <span class=\"hljs-keyword\">throws<\/span> DBException {\n  <span class=\"hljs-keyword\">var<\/span> sql = <span class=\"hljs-string\">\"SELECT AuthorID, FirstName, LastName, BirthDate FROM Authors\"<\/span>;\n\n  <span class=\"hljs-keyword\">var<\/span> authors = <span class=\"hljs-keyword\">new<\/span> ArrayList&lt;Author&gt;();\n\n  <span class=\"hljs-keyword\">try<\/span> (<span class=\"hljs-keyword\">var<\/span> statement = connection.createStatement();\n  <span class=\"hljs-keyword\">var<\/span> resultset = statement.executeQuery(sql)) {\n    <span class=\"hljs-comment\">\/\/<\/span>\n    <span class=\"hljs-keyword\">while<\/span> (resultset.next()) {\n      <span class=\"hljs-comment\">\/\/ create the author object<\/span>\n      authors.add(createAuthorFrom(resultset));\n    }\n\n    <span class=\"hljs-keyword\">return<\/span> authors;\n  } <span class=\"hljs-keyword\">catch<\/span>(SQLException e) {\n    <span class=\"hljs-keyword\">throw<\/span> <span class=\"hljs-keyword\">new<\/span> DBException(e.getMessage());\n  }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>How it works.<\/p>\n\n\n\n<p>First, construct a <code><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-select\/\">SELECT<\/a><\/code> statement that returns all rows from the <code>Authors<\/code> table:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">var<\/span> sql = <span class=\"hljs-string\">\"SELECT AuthorID, FirstName, LastName, BirthDate FROM Authors\"<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Second, create a new <code>ArrayList<\/code> of Author objects:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">var<\/span> authors = <span class=\"hljs-keyword\">new<\/span> ArrayList&lt;Author&gt;();<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Third, create a <code>Statement<\/code> object by calling the <code>createStatement<\/code> of the <code>Connection<\/code> object and execute the <code>SELECT<\/code> statement by calling the <code>executeQuery()<\/code> method of the <code>Statement<\/code> object:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">try<\/span> (<span class=\"hljs-keyword\">var<\/span> statement = connection.createStatement();\n     <span class=\"hljs-keyword\">var<\/span> resultset = statement.executeQuery(sql)) {<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The <code>executeQuery()<\/code> method returns a <code>ResultSet<\/code> object.<\/p>\n\n\n\n<p>Since we use the try-with-resources to manage the Statement and <code>ResultSet<\/code> objects, we don&#8217;t need to manually close them.<\/p>\n\n\n\n<p>Fourth, iterate over the rows in the result set by calling the <code>next()<\/code> method, create an <code>Author<\/code> object from the <code>ResultSet<\/code>, and add it to the list:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">while<\/span> (resultset.next()) {\n  authors.add(createAuthorFrom(resultset));\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Note that we&#8217;ll define the <code>createAuthorFrom()<\/code> method shortly.<\/p>\n\n\n\n<p>Fifth, return the authors list from the method:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-6\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">return<\/span> authors;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Finally, raise a <code>DBException<\/code> if an error occurs when querying data from the <code>Authors<\/code> table:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\">} <span class=\"hljs-keyword\">catch<\/span>(SQLException e) {\n  <span class=\"hljs-keyword\">throw<\/span> <span class=\"hljs-keyword\">new<\/span> DBException(e.getMessage());\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-7\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Step 2. Define the <code>createAuthorFrom()<\/code> method that creates a new <code>Author<\/code> object from a <code>ResultSet<\/code> object:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-8\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-function\"><span class=\"hljs-keyword\">private<\/span> Author <span class=\"hljs-title\">createAuthorFrom<\/span><span class=\"hljs-params\">(ResultSet resultset)<\/span> <span class=\"hljs-keyword\">throws<\/span> SQLException <\/span>{\n   <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-keyword\">new<\/span> Author(\n      resultset.getInt(<span class=\"hljs-string\">\"AuthorID\"<\/span>),\n      resultset.getString(<span class=\"hljs-string\">\"FirstName\"<\/span>),\n      resultset.getString(<span class=\"hljs-string\">\"LastName\"<\/span>),\n      resultset.getDate(<span class=\"hljs-string\">\"BirthDate\"<\/span>).toLocalDate()\n   );\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-8\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In this method, we call the <code>get*<\/code> method of the <code>ResultSet<\/code> object to retrieve <code>AuthorID<\/code>, <code>FirstName<\/code>, <code>LastName<\/code>, and <code>BirthDate<\/code> and return a new <code>Author<\/code> object created based on these values.<\/p>\n\n\n\n<p>Step 3. Modify the <code>main()<\/code> method of the Main class to use the <code>findAll()<\/code> method:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-9\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">import<\/span> java.sql.SQLException;\n\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-class\"><span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">Main<\/span> <\/span>{\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title\">main<\/span><span class=\"hljs-params\">(String&#91;] args)<\/span> <\/span>{\n        <span class=\"hljs-keyword\">try<\/span> (<span class=\"hljs-keyword\">var<\/span> connection = SQLServerConnection.connect()) {\n            <span class=\"hljs-keyword\">var<\/span> authorDB = <span class=\"hljs-keyword\">new<\/span> AuthorDB(connection);\n            <span class=\"hljs-keyword\">var<\/span> authors = authorDB.findAll();\n            <span class=\"hljs-keyword\">for<\/span> (<span class=\"hljs-keyword\">var<\/span> author: authors){\n                System.out.println(author);\n            }\n        } <span class=\"hljs-keyword\">catch<\/span> (SQLException | DBException e) {\n            System.err.println(e.getMessage());\n        }\n    }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-9\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>How it works.<\/p>\n\n\n\n<p>First, connect to the SQL Server:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-10\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">try<\/span> (<span class=\"hljs-keyword\">var<\/span> connection = SQLServerConnection.connect()) {<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-10\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Second, create a new <code>AuthorDB<\/code> object:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-11\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">var<\/span> authorDB = <span class=\"hljs-keyword\">new<\/span> AuthorDB(connection);<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-11\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Third, find all authors from the Authors table by calling the <code>findAll()<\/code> method:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-12\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">var<\/span> authors = authorDB.findAll();<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-12\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Fourth, display all authors:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-13\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">for<\/span> (<span class=\"hljs-keyword\">var<\/span> author: authors) {\n  System.out.println(author);\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-13\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Finally, display an error message if any exception occurs while selecting data:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-14\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\">} <span class=\"hljs-keyword\">catch<\/span>(SQLException | DBException e) {\n  System.err.println(e.getMessage());\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-14\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Step 4. Run the Java program.<\/p>\n\n\n\n<p>Here&#8217;s the partial output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-15\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\">Author{authorId=<span class=\"hljs-number\">1<\/span>, firstName=<span class=\"hljs-string\">'John'<\/span>, lastName=<span class=\"hljs-string\">'Doe'<\/span>, birthDate=<span class=\"hljs-number\">1990<\/span>-<span class=\"hljs-number\">12<\/span>-<span class=\"hljs-number\">31<\/span>}\nAuthor{authorId=<span class=\"hljs-number\">2<\/span>, firstName=<span class=\"hljs-string\">'Lisa'<\/span>, lastName=<span class=\"hljs-string\">'Rodriguez'<\/span>, birthDate=<span class=\"hljs-number\">1989<\/span>-<span class=\"hljs-number\">04<\/span>-<span class=\"hljs-number\">07<\/span>}\nAuthor{authorId=<span class=\"hljs-number\">3<\/span>, firstName=<span class=\"hljs-string\">'Susan'<\/span>, lastName=<span class=\"hljs-string\">'Williams'<\/span>, birthDate=<span class=\"hljs-number\">1941<\/span>-<span class=\"hljs-number\">08<\/span>-<span class=\"hljs-number\">16<\/span>}\n...<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-15\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='selecting-one-row-from-a-table'>Selecting one row from a table <a href=\"#selecting-one-row-from-a-table\" class=\"anchor\" id=\"selecting-one-row-from-a-table\" title=\"Anchor for Selecting one row from a table\">#<\/a><\/h2>\n\n\n\n<p>We&#8217;ll select an author by Id.<\/p>\n\n\n\n<p>Step 1. Modify the <code>AuthorDB<\/code> class and define a method <code>findById<\/code> to find the author by Id:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-16\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> Author <span class=\"hljs-title\">findById<\/span><span class=\"hljs-params\">(<span class=\"hljs-keyword\">int<\/span> authorId)<\/span> <span class=\"hljs-keyword\">throws<\/span> DBException <\/span>{\n\n  <span class=\"hljs-keyword\">var<\/span> sql = <span class=\"hljs-string\">\"SELECT AuthorID, FirstName, LastName, BirthDate FROM Authors WHERE AuthorID = ?\"<\/span>;\n\n  <span class=\"hljs-keyword\">try<\/span> (<span class=\"hljs-keyword\">var<\/span> statement = connection.prepareStatement(sql)) {\n    <span class=\"hljs-comment\">\/\/ Bind values to parameters<\/span>\n    statement.setInt(<span class=\"hljs-number\">1<\/span>, authorId);\n\n    <span class=\"hljs-comment\">\/\/ Execute the query<\/span>\n    <span class=\"hljs-keyword\">try<\/span> (<span class=\"hljs-keyword\">var<\/span> resultset = statement.executeQuery()) {\n      <span class=\"hljs-comment\">\/\/<\/span>\n      <span class=\"hljs-keyword\">if<\/span> (!resultset.next()) {\n        <span class=\"hljs-keyword\">throw<\/span> <span class=\"hljs-keyword\">new<\/span> DBException(<span class=\"hljs-string\">\"The author with id \"<\/span> + authorId + <span class=\"hljs-string\">\" not found.\"<\/span>);\n      }\n\n      <span class=\"hljs-comment\">\/\/ create the author object<\/span>\n      <span class=\"hljs-keyword\">return<\/span> createAuthorFrom(resultset);\n\n    }\n\n  } <span class=\"hljs-keyword\">catch<\/span>(SQLException e) {\n    <span class=\"hljs-keyword\">throw<\/span> <span class=\"hljs-keyword\">new<\/span> DBException(e.getMessage());\n  }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-16\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>How it works.<\/p>\n\n\n\n<p>First, construct a <code>SELECT<\/code> statement that returns all rows from the <code>Authors<\/code> table:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-17\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">var<\/span> sql = <span class=\"hljs-string\">\"SELECT AuthorID, FirstName, LastName, BirthDate FROM Authors WHERE AuthorID = ?\"<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-17\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Second, create a <code>PreparedStatement<\/code> object by calling the <code>prepareStatement()<\/code> method of the Connection object:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-18\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">try<\/span> (<span class=\"hljs-keyword\">var<\/span> statement = connection.prepareStatement(sql)) {<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-18\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In this example, we use the <code>PreparedStatement<\/code> because the query has a parameter <code>AuthorID<\/code>.<\/p>\n\n\n\n<p>Third, bind the value to the query:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-19\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\">statement.setInt(<span class=\"hljs-number\">1<\/span>, authorId);<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-19\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Fourth, execute the query to select data from the <code>Authors<\/code> table by calling the <code>executeQuery()<\/code> method of the <code>PreparedStatement<\/code> object:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-20\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">try<\/span> (<span class=\"hljs-keyword\">var<\/span> resultset = statement.executeQuery()) {<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-20\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Fifth, throw an exception if no author with the specified Id exists:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-21\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">if<\/span> (!resultset.next()) {\n  <span class=\"hljs-keyword\">throw<\/span> <span class=\"hljs-keyword\">new<\/span> DBException(<span class=\"hljs-string\">\"The author with id \"<\/span> + authorId + <span class=\"hljs-string\">\" not found.\"<\/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\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Sixth, return the <code>Author<\/code> object created from the result:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-22\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">return<\/span> createAuthorFrom(resultset);<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-22\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Seventh, throw a <code>DBException<\/code> if an error occurs while selecting the data:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-23\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\">} <span class=\"hljs-keyword\">catch<\/span>(SQLException e) {\n  <span class=\"hljs-keyword\">throw<\/span> <span class=\"hljs-keyword\">new<\/span> DBException(e.getMessage());\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-23\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Step 2. Modify the <code>main()<\/code> method of the <code>Main<\/code> class to use the <code>findById()<\/code> method:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-24\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">import<\/span> java.sql.SQLException;\n\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-class\"><span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">Main<\/span> <\/span>{\n    <span class=\"hljs-function\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title\">main<\/span><span class=\"hljs-params\">(String&#91;] args)<\/span> <\/span>{\n        <span class=\"hljs-keyword\">try<\/span> (<span class=\"hljs-keyword\">var<\/span> connection = SQLServerConnection.connect()) {\n            <span class=\"hljs-keyword\">var<\/span> authorDB = <span class=\"hljs-keyword\">new<\/span> AuthorDB(connection);\n\n            <span class=\"hljs-comment\">\/\/ find author by Id<\/span>\n            <span class=\"hljs-keyword\">var<\/span> author = authorDB.findById(<span class=\"hljs-number\">1<\/span>);\n            System.out.println(author);\n\n        } <span class=\"hljs-keyword\">catch<\/span> (SQLException | DBException e) {\n            System.err.println(e.getMessage());\n        }\n    }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-24\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Step 3. Run the Java program.<\/p>\n\n\n\n<p>Here&#8217;s the output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-25\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\">Author{authorId=<span class=\"hljs-number\">1<\/span>, firstName=<span class=\"hljs-string\">'John'<\/span>, lastName=<span class=\"hljs-string\">'Doe'<\/span>, birthDate=<span class=\"hljs-number\">1990<\/span>-<span class=\"hljs-number\">12<\/span>-<span class=\"hljs-number\">31<\/span>}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-25\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>If you change the author Id to a value that does not exist, for example:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-26\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\"><span class=\"hljs-keyword\">var<\/span> author = authorDB.findById(-<span class=\"hljs-number\">1<\/span>);<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-26\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>you&#8217;ll get the following message:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-27\" data-shcb-language-name=\"Java\" data-shcb-language-slug=\"java\"><span><code class=\"hljs language-java\">The author with id -<span class=\"hljs-number\">1<\/span> not found.<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-27\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">Java<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">java<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='download-the-project-source-code'>Download the project source code <a href=\"#download-the-project-source-code\" class=\"anchor\" id=\"download-the-project-source-code\" title=\"Anchor for Download the project source code\">#<\/a><\/h2>\n\n\n\n<p><a href=\"https:\/\/www.sqlservertutorial.net\/wp-content\/uploads\/select.zip\">Download the project source code<\/a><\/p>\n\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>Call the <code>executeQuery()<\/code> of the Statement or <code>PreparedStatement<\/code> object to execute a query and return a <code>ResultSet<\/code> object.<\/li>\n\n\n\n<li>Call the <code>next()<\/code> method of the <code>ResultSet<\/code> object to iterate over the rows from the result set.<\/li>\n\n\n\n<li>Use the <code>get*<\/code> method to retrieve data from each row in the result set.<\/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 class=\"wth-thumbs\">\n\t\t\t<button\n\t\t\t\tdata-post=\"4264\"\n\t\t\t\tdata-post-url=\"https:\/\/www.sqlservertutorial.net\/java-sql-server\/java-sql-server-select\/\"\n\t\t\t\tdata-post-title=\"Java SQL Server: Selecting Data\"\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 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