mysqlstored-proceduresprepare

MySQL PREPARE statement in stored procedures

I have this sql file:

USE mydb;

DROP PROCEDURE IF EXISTS execSql;
DELIMITER //
CREATE PROCEDURE execSql (
                     IN sqlq VARCHAR(5000)
                      ) COMMENT 'Executes the statement'
BEGIN
  PREPARE stmt FROM sqlq;
  EXECUTE stmt;
  DEALLOCATE PREPARE stmt;
END //
DELIMITER ;

When I try to run it with

# cat file.sql | mysql -p

I get

ERROR 1064 (42000) at line 6: You have an error in your SQL syntax; check the manual
that corresponds to your MySQL server version for the right syntax to use near 'sqlq;
  EXECUTE stmt;
  DEALLOCATE PREPARE stmt;
  END' at line 5

What am I doing wrong?

Solution

  • You can only prepare and execute SQL that's a string literal or a user-defined variable that contains the text of the statement.

    Try this:

    USE mydb;

DROP PROCEDURE IF EXISTS execSql;
DELIMITER //

CREATE PROCEDURE execSql (IN sqlq VARCHAR(5000)) COMMENT 'Executes the statement'
BEGIN
  SET @sqlv = sqlq;
  PREPARE stmt FROM @sqlv;
  EXECUTE stmt;
  DEALLOCATE PREPARE stmt;
END //

DELIMITER ;