PHP MySQL - Inner Join only if not null - php

Question

I have a mysqli SELECT query that is using an Inner Join and I noticed a big problem: it doesn't select rows where the column value for the condition is null (because NULL doesn't exist in the second table). Here's my code:
<?php
$sql = mysqli_connect(/* CONNECTION */);
$query = "SELECT " .
"e.EQUIPMENT_ID, " .
"e.CUSTOMER_ID, " .
"e.DESCRIPTION, " .
"e.LOCATION, " .
"e.JOB_SITE, " .
"e.PROJECT_NAME, " .
"jb.DESCRIPTION AS JOB_SITE_NAME " .
"FROM equipments e " .
"INNER JOIN jobsites jb ON jb.JOBSITE_ID = e.JOB_SITE " .
"WHERE e.CUSTOMER_ID = 1 ".
"ORDER BY e.EQUIPMENT_ID ASC";
$results = mysqli_query($sql, $query);
if(!isset($data)) $data = array(); $cc = 0;
while($info = mysqli_fetch_array($results, MYSQLI_ASSOC)){
if(!isset($data[$cc])) $data[$cc] = array();
///// FROM TABLE equipments /////
$data[$cc]['EQUIPMENT_ID'] = $info['EQUIPMENT_ID'];
$data[$cc]['DESCRIPTION'] = $info['DESCRIPTION'];
$data[$cc]['LOCATION'] = $info['LOCATION'];
$data[$cc]['PROJECT_NAME'] = $info['PROJECT_NAME'];
$data[$cc]['JOB_SITE_ID'] = $info['JOB_SITE'];
///// FROM TABLE jobsites /////
$data[$cc]['JOB_SITE'] = $info['JOB_SITE_NAME'];
$cc++;
}
print_r($data);
?>
So, as I said, the code returns values but only if the column "JOB_SITE" inside "equipments" has a jobsite id (not null). The ugly solution is to create a row inside the table "jobsites" with a jobsite_id named "empty", but if I can skip this, I will.
Is there a way to join only if e.JOB_SITE is not null ?

Answer 1

You can use LEFT JOIN in SQL query.
$query = "SELECT " .
"e.EQUIPMENT_ID, " .
"e.CUSTOMER_ID, " .
"e.DESCRIPTION, " .
"e.LOCATION, " .
"e.JOB_SITE, " .
"e.PROJECT_NAME, " .
"jb.DESCRIPTION AS JOB_SITE_NAME " .
"FROM equipments e " .
"LEFT JOIN jobsites jb ON jb.JOBSITE_ID = e.JOB_SITE " .
"WHERE e.CUSTOMER_ID = 1 ".
"ORDER BY e.EQUIPMENT_ID ASC";
This query will return NULL VALUE for column JOB_SITE_NAME if there is no row matching jb.JOBSITE_ID in equipments table