PHP MySQL : Where Clause

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Klausa WHERE digunakan untuk mengekstraksi hanya dokumen yang memenuhi kondisi tertentu.

Sintaks dasar klausa WHERE dapat diberikan dengan:

Mari kita membuat query SQL menggunakan klausa WHERE dalam pernyataan SELECT, setelah itu kita akan mengeksekusi query ini dengan mengirimkannya ke fungsi PHP mysqli_query() untuk mendapatkan data yang difilter.

Pertimbangkan kita memiliki tabel persons di dalam basis data demo yang memiliki dokumen berikut:

id | first_name | last_name | email                |
+----+------------+-----------+----------------------+
|  1 | Peter      | Parker    | peterparker@mail.com |
|  2 | John       | Rambo     | johnrambo@mail.com   |
|  3 | Clark      | Kent      | clarkkent@mail.com   |
|  4 | John       | Carter    | johncarter@mail.com  |
|  5 | Harry      | Potter    | harrypotter@mail.com

Kode PHP berikut men-select semua baris dari tabel persons di mana first_name=’john’:

<?php
/* Attempt MySQL server connection. Assuming you are running MySQL
server with default setting (user 'root' with no password) */
$link = mysqli_connect("localhost", "root", "", "demo");
 
// Check connection
if($link === false){
    die("ERROR: Could not connect. " . mysqli_connect_error());
}
 
// Attempt select query execution
$sql = "SELECT * FROM persons WHERE first_name='john'";
if($result = mysqli_query($link, $sql)){
    if(mysqli_num_rows($result) > 0){
        echo "<table>";
            echo "<tr>";
                echo "<th>id</th>";
                echo "<th>first_name</th>";
                echo "<th>last_name</th>";
                echo "<th>email</th>";
            echo "</tr>";
        while($row = mysqli_fetch_array($result)){
            echo "<tr>";
                echo "<td>" . $row['id'] . "</td>";
                echo "<td>" . $row['first_name'] . "</td>";
                echo "<td>" . $row['last_name'] . "</td>";
                echo "<td>" . $row['email'] . "</td>";
            echo "</tr>";
        }
        echo "</table>";
        // Close result set
        mysqli_free_result($result);
    } else{
        echo "No records matching your query were found.";
    }
} else{
    echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}
 
// Close connection
mysqli_close($link);
?>

Setelah filtrasi set hasil akan terlihat seperti ini:

+----+------------+-----------+---------------------+
| id | first_name | last_name | email               |
+----+------------+-----------+---------------------+
|  2 | John       | Rambo     | johnrambo@mail.com  |
|  4 | John       | Carter    | johncarter@mail.com |
+----+------------+-----------+---------------------+