 <p>Whatever <code>JOIN</code> syntax you've used there, I'm not familiar with it. You also had the following, which is incorrect:</p> <pre><code>`j`.`user_id=$user_id` </code></pre> <p>If you're going to use the backticks, it would be this:</p> <pre><code>`j`.`user_id` = $user_id </code></pre> <p>Assuming <code>$user_id</code> is an integer (I also put single quotes around this type in the <code>WHERE</code> clause in case <code>$user_id</code> is empty for some reason; this helps prevent unnecessary syntax errors). However, backticks are rarely necessary (when column names are also reserved words or there is a space, for instance).</p> <p>Putting it together, with my own syntax style:</p> <pre><code>SELECT j.job_id , j.user_id , b.business_name , b.contract_person , b.mobile_number , b.email , b.id FROM ci_jobs_apply AS j INNER JOIN ci_business AS b ON j.job_id = b.id WHERE j.user_id = '$user_id' </code></pre>