选择查询存储过程

Question

I want to call a procedure with some conditions, This is my code.

DELIMITER $$

USE `jijo_db`$$

DROP PROCEDURE IF EXISTS `view_all_user_details_with_limit`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `view_all_user_details_with_limit`(IN StartNo INT,IN EndNo INT, IN OrderVal VARCHAR(10),IN Cond VARCHAR(50))
BEGIN   
SELECT * FROM `tbl_user_details` WHERE  Cond  ORDER BY OrderVal LIMIT StartNo,EndNo;
END$$

DELIMITER ;

procedure call - CALL view_all_user_details_with_limit(0,10,'',"NAME LIKE '%a%'");

but I dont get any result. why ????

Answer 1

If you want to have variable WHERE , LIMIT , and ORDER BY conditions, you will need to create a prepared statement in your stored procedure.

Try something like this:

DELIMITER $$

USE `jijo_db`$$

DROP PROCEDURE IF EXISTS `view_all_user_details_with_limit`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `view_all_user_details_with_limit`(IN StartNo INT,IN EndNo INT, IN OrderVal VARCHAR(10),IN Cond VARCHAR(50))
BEGIN
   SET @q = CONCAT('SELECT * FROM `tbl_user_details` WHERE ', Cond);
   IF OrderVal != '' THEN
      SET @q = CONCAT(@q, ' ORDER BY ', OrderVal);
   END IF;
   SET @q = CONCAT(@q, ' LIMIT ', StartNo, ', ', EndNo - StartNo + 1);
   PREPARE stmt FROM @q;
   EXECUTE stmt;
END$$

DELIMITER ;

Answer 2

Your problem seems to be happening in WHERE Cond .

A MySQL Stored Procedure won't interpret that string as an expression, but will instead attempt to cast it to a Boolean.

You can see by running SELECT CAST("NAME LIKE '%a%'" AS UNSIGNED); that the string will be interpreted as False, and thereby you won't get any results.

I suggest instead that you accept in your Cond variable a string such as '%a%' and then update your query to:

SELECT * 
FROM `tbl_user_details` 
WHERE `NAME` LIKE Cond
ORDER BY OrderVal
LIMIT StartNo, EndNo;