Select statement inside a loop in a Mysql Stored Procedure

Question

Can we use Select statement inside a loop in a Mysql Stored Procedure?

why is the code wrong

create procedure AbsentReportproc (INOUT fromdate DATET         


        

Answer 1

Try this:

DELIMITER $$

DROP PROCEDURE IF EXISTS `AbsentReportproc`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `AbsentReportproc`(IN _fromdate DATETIME, IN _todate DATETIME)
BEGIN 
    CREATE TEMPORARY TABLE daterange (dte DATE); 

    SET @counter := -1;
    WHILE (@counter < DATEDIFF(DATE(_todate), DATE(_fromdate))) DO 
        INSERT daterange VALUES (DATE_ADD(_fromdate, INTERVAL @counter:=@counter + 1 DAY));
    END WHILE;

    SELECT tp.cardno, tp.EMPCODE, tp.DEPARTMENT, GROUP_CONCAT(d.dte) Absentddate, COUNT(tp.cardno) Totalnoofabsentdates
    FROM test_prefixmaster tp JOIN daterange d 
    LEFT JOIN test_prefixtransactions tpt ON tp.cardno = tpt.CARDNO AND DATE(S_DateTime) = d.dte
    WHERE tpt.CARDNO IS NULL 
    GROUP BY tp.cardno;

    DROP TABLE daterange;
END$$

DELIMITER ;

Answer 2

You didn't need a loop for this. You can do so:

SELECT
  p.CARDNO, 
  COUNT(CARDNO) AS countdate
FROM test_prefixmaster p
INNER JOIN test_prefixtransactions   t ON p.CARDNO = t.CARDNO
WHERE Date(t.S_DateTime) BETWEEN fromdate 
                             AND todate
GROUP BY p.CARDNO;