DB2 CASE/IF 条件控制语句

della0887

IF语句格式(仅仅限于DB2过程、触发器、函数中使用)IF (条件)
THEN 语句;
ELSEIF (条件)
THEN 语句;
ELSEIF (条件)
THEN 语句;
... ...
ELSE
语句;
END IF;

例子：
BEGIN--取出最大ID   SET NEW_ID=NULL;  -- (SELECT TOP 1 my_id from TEMPVOUCHERNO ORDER BY my_id DESC)SET NEW_ID=(SELECT my_id FROM "PIGGY".TEMPVOUCHERNO FETCH FIRST 1 ROWS ONLY);--如果未取出来   IF NEW_ID IS NULLTHEN SET NEW_ID='0000001';ELSEBEGINDECLARE NUM VARCHAR(7);--取出编号+1  CONVERT(VARCHAR,(CONVERT(INTEGER,RIGHT(NEW_ID,7))+1));--CAST((CAST(RIGHT(NEW_ID,7) as INTEGER)+1) as VARCHAR(7));--SET NUM=CONVERT(VARCHAR(7),(CONVERT(INTEGER,RIGHT(NEW_ID,7))+1));--SET NUM=REPLICATE('0',7-LEN(NUM))+NUM;SET NEW_ID=NUM; END;END IF;insert into "PIGGY".TEMPVOUCHERNO (my_id) values(NEW_ID);END