How Can Prepared Statements Improve the Efficiency and Security of LIKE Searches?

Optimizing LIKE Searches with Prepared Statements

Database queries using the LIKE operator for pattern matching require careful handling to prevent vulnerabilities and ensure performance. Improper use can lead to errors.

Let's examine some flawed approaches:

<code class="language-sql">$sql = 'SELECT * FROM `users` WHERE username LIKE \'%{?}%\' ';</code>

This fails because the number of variables in the SQL string doesn't match the parameters provided to bind_param().

<code class="language-sql">$sql = 'SELECT * FROM `users` WHERE username LIKE %{?}% ';</code>

This results in a syntax error due to incorrect placement of wildcard characters (%{}) within the query string.

The correct method uses prepared statements, employing a question mark placeholder and binding the variable appropriately:

<code class="language-php">$likeVar = "%" . $yourParam . "%";
$stmt = $mysqli->prepare("SELECT * FROM REGISTRY where name LIKE ?");
$stmt->bind_param("s", $likeVar);
$stmt->execute();</code>

This code:

1. Constructs the pattern by concatenating percentage signs to the user input ($yourParam).
2. Prepares the query with a ? placeholder.
3. Binds the pattern string ("s" for string) using bind_param().
4. Executes the prepared statement.

Using prepared statements with LIKE prevents SQL injection and enhances query efficiency.

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