Question

I have make one procedure which has in and out parameter:

delimiter //
DROP PROCEDURE IF EXISTS empInfo ; 
CREATE PROCEDURE empInfo (tblname VARCHAR(50),
                          clName VARCHAR(50),
                          out total INT)
BEGIN

 SET @s = CONCAT("SELECT count(", clName ,") into total FROM ", tblname );
 PREPARE stmt FROM @s;
 EXECUTE stmt;

END//

Here I’m going to call above procedure in mysql.

mysql> CALL empInfo('emp','empid', @total);

It creates successfully, but when I use it – it doesn’t work properly.

Answer 1

seems alright to me but just dun work somehow
here is the workaround :

delimiter //
DROP PROCEDURE IF EXISTS empInfo ;
CREATE PROCEDURE empInfo (in tblname VARCHAR(255), in clName VARCHAR(255))
BEGIN
  SET @s = CONCAT("SELECT count(", clName ,") into @total FROM ", tblname);
  PREPARE stmt FROM @s;
  EXECUTE stmt;
END//
delimiter ;
CALL empInfo('emo','empid');
select @total;