PHP MySQL Where

In this tutorial you will learn how to select the records from a MySQL database table based on specific conditions using PHP.

## Filtering the Records
The [WHERE](http://www.bixiaguangnian.com/manual/sql/3394.html "WHERE") clause is used to extract only those records that fulfill a specified condition.

The basic syntax of the `WHERE` clause can be given with:

```sql
SELECT column_name(s) FROM table_name WHERE column_name operator value
```
Let's make a SQL query using the `WHERE` clause in `SELECT` statement, after that we'll execute this query through passing it to the PHP `mysqli_query()` function to get the filtered data.

Consider we've a persons table inside the demo database that has following records:

```php
<?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);
?>
```
After filtration the result set will look something like this: