Select Query with Stored Procedure - mysql

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;