What is the purpose of the nested SELECT query in the PHP code provided?

The purpose of the nested SELECT query in the PHP code provided is to retrieve data from a database table based on the results of an outer SELECT query. This allows for more complex and specific data retrieval operations by using the results of the outer query as a condition for the inner query. 

// Nested SELECT query in PHP code
$query = "SELECT * FROM table1 WHERE column1 = (SELECT column2 FROM table2 WHERE condition)";
$result = mysqli_query($connection, $query);

// Example of fixing the nested SELECT query
$query = "SELECT column2 FROM table2 WHERE condition";
$innerResult = mysqli_query($connection, $query);
$row = mysqli_fetch_assoc($innerResult);
$column2Value = $row['column2'];

$query = "SELECT * FROM table1 WHERE column1 = '$column2Value'";
$result = mysqli_query($connection, $query);

Keywords

nested SELECT query PHP code purpose SQL data retrieval

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