What is the process of connecting two SQL queries in PHP to retrieve specific data from a table based on the results of the first query?

When connecting two SQL queries in PHP to retrieve specific data from a table based on the results of the first query, you can use a subquery or a JOIN statement. Subqueries can be nested within the WHERE clause of the main query to filter results based on the output of the subquery. Alternatively, a JOIN statement can be used to combine the results of two queries based on a common column. 

<?php
// First query to retrieve specific data
$query1 = "SELECT id, name FROM table1 WHERE condition = 'value'";
$result1 = mysqli_query($connection, $query1);

// Loop through the results of the first query
while ($row = mysqli_fetch_assoc($result1)) {
    $id = $row['id'];
    
    // Second query using the result of the first query
    $query2 = "SELECT * FROM table2 WHERE id = $id";
    $result2 = mysqli_query($connection, $query2);
    
    // Process the results of the second query
    while ($data = mysqli_fetch_assoc($result2)) {
        // Do something with the data
    }
}
?>

Keywords

PHP SQL queries data retrieval table connection

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