How to Fix 'Cannot Pass Parameter by Reference' Errors When Using PDO bindParam with Constants?

Resolving "Cannot Pass Parameter by Reference" Error with bindParam When Using Constants

When utilizing Prepared Statements with constants, an error like "Cannot pass parameter 2 by reference" might arise. Unlike bindParam, which works with references and does not pull in values during bindParam execution, bindValue is intended for this purpose.

The problematic code:

$stmt->bindParam(':v1', PDO::PARAM_NULL);

To resolve this issue, replace bindParam with bindValue and provide a constant value as an argument.

$stmt->bindValue(':v1', null, PDO::PARAM_INT);

Please note that using PDO::PARAM_NULL in bindValue might not work for everyone. Instead, use PDO::PARAM_INT or an appropriate constant that matches the data type of the column.

Additionally, when using bindValue, you should specify the data type using the third argument. This ensures that the database handles the value correctly.

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