How can the incorrect usage of quotes in PHP arrays affect the execution of MySQL queries in PHP scripts?

Incorrect usage of quotes in PHP arrays can affect the execution of MySQL queries in PHP scripts by causing syntax errors in the SQL queries. This is because quotes are used to delimit strings in SQL queries, and if quotes are not used correctly in PHP arrays, the SQL query may not be constructed properly, leading to errors. To solve this issue, make sure to properly use quotes when constructing SQL queries in PHP arrays to ensure the queries are executed correctly.

// Incorrect usage of quotes in PHP array
$data = array(
    'name' => 'John',
    'age' => 30
);

// Incorrect SQL query construction
$sql = "INSERT INTO users (name, age) VALUES ('$data['name']', $data['age'])";

// Corrected SQL query construction
$sql = "INSERT INTO users (name, age) VALUES ('" . $data['name'] . "', " . $data['age'] . ")";