How to Preserve NULL Values in MySQLi Prepared Statements?

Passing NULL in MySQLi Prepared Statements

In a MySQLi prepared statement, NULL values are automatically converted to '' (strings) or 0 (integers). However, it may be desired to store NULL values without any conversion.

Solution:

To preserve NULL values, the mysql NULL safe operator must be used. This operator is written as '<=>' and checks if the value is equal to NULL.

Example:

The following code snippet demonstrates the use of the NULL safe operator to select products with NULL prices:

<code class="php">$price = NULL; // NOTE: no quotes - using php NULL
$stmt = $mysqli->prepare("SELECT id FROM product WHERE price <=> ?"); // Will select products where the price is null
$stmt->bind_param('i', $price);</code>

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