Why Does My C# Prepared Statement with MySQL Fail, But a Regular Statement Works?

Troubleshooting Prepared Statement Issues in C# with MySql

You've encountered a stumbling block while implementing a prepared statement in your C# program. Upon transitioning to a regular statement, your code operates seamlessly, leaving you puzzled. Let's investigate the potential culprit behind this discrepancy.

In the code snippet you provided:

cmd = new MySqlCommand("SELECT * FROM admin WHERE admin_username='@val1' AND admin_password=PASSWORD('@val2')", MySqlConn.conn);
//cmd.Prepare();
//cmd.Parameters.AddWithValue("@val1", tboxUserName.Text);
//cmd.Parameters.AddWithValue("@val2", tboxPassword.Text);
cmd = new MySqlCommand("SELECT * FROM admin WHERE admin_username='"+tboxUserName.Text+"' AND admin_password=PASSWORD('"+tboxPassword.Text+"')", MySqlConn.conn);

The key distinction lies in the usage of single quotes (' ') in the SQL query. Prepared statements leverage parameter placeholders (@val1, @val2) to prevent SQL injection attacks. When employing regular statements, you must escape the single quotes within the query itself.

To resolve this issue, consider modifying your code as follows:

cmd = new MySqlCommand("SELECT * FROM admin WHERE admin_username=@val1 AND admin_password=PASSWORD(@val2)", MySqlConn.conn);
cmd.Parameters.AddWithValue("@val1", tboxUserName.Text);
cmd.Parameters.AddWithValue("@val2", tboxPassword.Text);
cmd.Prepare();

By removing the single quotes ' from the query and using cmd.Prepare() after adding parameters, you ensure that the prepared statement is functional. This approach safeguards your code against malicious injections and enhances its security.

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