How to Properly Use Wildcards with PDO Prepared Statements?

Wildcard Usage in PDO Prepared Statements

Executing SQL queries often involves filtering data based on specific criteria. Prepared statements are a secure way to achieve this by preventing SQL injection vulnerabilities. However, using wildcards in prepared statements can pose challenges.

The Challenge

Consider the following query that aims to search for users whose name contains "anyname":

SELECT * FROM `gc_users` WHERE `name` LIKE '%anyname%'

When trying to execute this query with prepared statements, common approaches like:

$stmt = $dbh->prepare("SELECT * FROM `gc_users` WHERE `name` LIKE :name");
$stmt->bindParam(':name', "%" . $name . "%");

and

$stmt = $dbh->prepare("SELECT * FROM `gc_users` WHERE `name` LIKE '%:name%'");
$stmt->bindParam(':name', $name);

may fail to work. This is because using wildcards in the SQL LIKE statement requires special handling within prepared statements.

The Solution

To correctly use wildcards with prepared statements, one can utilize the bindValue() method instead of bindParam(). Here's an example:

$stmt = $dbh->prepare("SELECT * FROM `gc_users` WHERE `name` LIKE :name");
$stmt->bindValue(':name', '%' . $name . '%');

Alternatively, bindParam() can be used, but with a slightly modified syntax:

$name = "%$name%";
$stmt = $dbh->prepare("SELECT * FROM `gc_users` WHERE `name` like :name");
$stmt->bindParam(':name', $name);

Both approaches ensure that the wildcard characters are properly escaped and handled by the database. By using bindValue() or bindParam() in this manner, one can effectively search for data using wildcards within prepared statements, ensuring both security and functionality.

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