SQL LEFT JOIN Syntax
SELECT column_name list
FROM table1
LEFT JOIN table2 ON table1.column_name=table2.column_name;
or:
SELECT column_name list
FROM table1
LEFT OUTER JOIN table2 ON table1.column_name=table2.column_name;
Lets Learn.
1.Create database and two tables
Course table.(left table)
CourseID | CourseName | CourseCode |
---|---|---|
1 | Mechanical | ME20 |
2 | Chemical | C20 |
3 | Civil | CL20 |
4 | Electrical | E20 |
5 | Computer | CS20 |
6 | Information | IS20 |
7 | Electrical Electronics | EE20 |
8 | Electrical Communication | ECE20 |
Student table.(right table)
StudentID | StudentName | Address | Section | Branch | Percentage | CourseID |
---|---|---|---|---|---|---|
1 | Liam | 23 Andrew road | A | CSE | 66 | 5 |
2 | Andrew | 2415 Anthony market str | A | ISE | 80 | 5 |
5 | Charles | 878 Eli Berguvsvägen 8 | C | ECE | 52 | 9 |
9 | Andrew | 2415 Anthony market str | A | CE | 80 | 2 |
10 | Bhavya | 18 Christopher sq. | B | CE | 67 | 9 |
12 | Rajesh | 878 Eli Berguvsvägen 8 | C | CL | 52 | 3 |
13 | Daniel | 878 Eli Berguvsvägen 8 | ME | CSE | 52 | 8 |
15 | Connor | 878 Eli Berguvsvägen 8 | C | ME | 52 | 1 |
16 | Kiran | 878 Eli Berguvsvägen 8 | ME | ECE | 52 | 10 |
SELECT course.CourseName ,student.StudentID
FROM course
LEFT JOIN student ON course.CourseID = student.StudentID
ORDER BY course.CourseName;
<!DOCTYPE html>
<html lang="en">
<head>
<title>SQL LEFT JOIN </title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
</head>
<body>
<div class="container">
<div class="text-center">
<h1>SQL LEFT JOIN</h1>
</div>
<div class="well">
<?php
$connect = mysqli_connect("localhost", "root", "", "school_management");
if ($connect->connect_error) {
die("Connection failed: " . $connect->connect_error);
}
$sql_1 = "SELECT course.CourseName ,student.StudentID
FROM course
LEFT JOIN student ON course.CourseID = student.StudentID
ORDER BY course.CourseName;";
echo "<h2 class='text-danger'>SQL LEFT JOIN</h2>";
if($result_1 = mysqli_query($connect, $sql_1)){
if(mysqli_num_rows($result_1) > 0){
echo "<table class='table'>
<tr>
<th>StudentID</th>
<th>CourseName</th>
</tr>
";
while($row = $result_1->fetch_assoc()){
echo "<tr>
<td>".$row['StudentID'] /*student table*/ ."</td>
<td>".$row['CourseName'] /*student table*/ ."</td>
</tr>";
}
echo "</table>";
} else{
echo "No records found.";
}
}
?>
</div>
<br>
</div>
</body>
</html>