MySQL存储过程如果存在

Question

I'm creating a stored procedure in MySQL, and having trouble using IF EXISTS

CREATE DEFINER=`##`@`%` PROCEDURE `myTestProceedure`(IN _id INT)
BEGIN
    IF EXISTS (SELECT * FROM cms.variables WHERE tmplvarid = 5 and id = _id) THEN
    BEGIN
    UPDATE cms.variables SET value = now() WHERE id = _id and tmplvarid = 5;
    END;
    ELSE 
    BEGIN
    INSERT INTO cms.variables (`tmplvarid`, `contentid`, `value`) VALUES (5, _id, now());
    END;
    END IF;
END

Answer 1

try this:

CREATE DEFINER=`##`@`%` PROCEDURE `myTestProceedure`(IN _id INT)
BEGIN
    IF (SELECT count(*) FROM cms.variables WHERE tmplvarid = 5 and id = _id)>0 THEN
    BEGIN
    UPDATE cms.variables SET value = now() WHERE id = _id and tmplvarid = 5;
    END;
    ELSE 
    BEGIN
    INSERT INTO cms.variables (`tmplvarid`, `contentid`, `value`) VALUES (5, _id, now());
    END;
    END IF;
END

Answer 2

The accepted answer didn't work for me running MariaDB 15.1. It just kept evaluating the IF condition as true and trying to insert the record even if it already existed.

CREATE DEFINER=`ghost`@`localhost` PROCEDURE `proc_updateTable`(IN `_id` mediumint,IN `_arg2` varchar(100))
BEGIN
    #Routine body goes here...
    DECLARE exist DECIMAL DEFAULT 0;
    SELECT COUNT(*) INTO exist FROM `database`.`tbl_example` WHERE (`tbl_example`.`ID` = _id AND `tbl_example`.`arg2` = _arg2);
    IF exist < 1 THEN
        BEGIN
            INSERT INTO `database`.`tbl_example` VALUES (_id,_arg2);
        END;
    END IF;
END