MySQL存儲過程如果存在

Question

我正在 MySQL 中創建一個存儲過程，但在使用 IF EXISTS 時遇到了問題

我的 SQL 是；

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

嘗試這個：

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

接受的答案對我運行 MariaDB 15.1 不起作用。 它只是不斷地將 IF 條件評估為真，並嘗試插入記錄，即使它已經存在。

這就是我最終使用的：

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