Mysql游标
14.6.6.2 Cursor DECLARE Syntax
Cursor可内嵌于存储过程之中,有三个属性:Asensitive(),Read only(只读),Nonscrollable(单向逐行)。其声明位于Handler之后,变量声明之前。
CREATE PROCEDURE curdemo() BEGIN DECLARE done INT DEFAULT FALSE; DECLARE a CHAR(16); DECLARE b, c INT; DECLARE cur1 CURSOR FOR SELECT id,data FROM test.t1; DECLARE cur2 CURSOR FOR SELECT i FROM test.t2; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE; OPEN cur1; OPEN cur2; read_loop: LOOP FETCH cur1 INTO a, b; FETCH cur2 INTO c; IF done THEN LEAVE read_loop; END IF; IF b < c THEN INSERT INTO test.t3 VALUES (a,b); ELSE INSERT INTO test.t3 VALUES (a,c); END IF; END LOOP; CLOSE cur1; CLOSE cur2; END;