Question

I have the following stored procedure:

DELIMITER ///

CREATE PROCEDURE tmp_test_proc(__TABLE__NAME varchar(255))
BEGIN
  SELECT COUNT(*) FROM __TABLE__NAME;
END///

DELIMITER ;

I would like to select from the parameter __TABLE__NAME, but MySQL tells me there is no table __TABLE__NAME… So is there a way to use the value of the parameter in the from clause?

Answer 1

you cannot parameterized table names (as well as column names) by default, you need to create PreparedStatement for this,

DELIMITER ///

CREATE PROCEDURE tmp_test_proc(__TABLE__NAME varchar(255))
BEGIN
    SET @sql = CONCAT('SELECT COUNT(*) FROM ', __TABLE__NAME);

    PREPARE stmt FROM @sql;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;
END///

DELIMITER ;