mysql遊標循環的三種方式及打印結果查看
2017年03月14日 11:34:22 nannan1232 閱讀數：9325
1、while方式：
DELIMITER
USE `ct1_test`
DROP PROCEDURE IF EXISTS `searchDate`
CREATE DEFINER=`greesj1b`@`%` PROCEDURE `searchDate`()
BEGIN
DECLARE tmpName VARCHAR(20) DEFAULT '' ;
DECLARE temp_id VARCHAR(1024) DEFAULT '' ;
DECLARE cur1 CURSOR FOR SELECT _id FROM `wp04_project` ORDER BY _id ASC LIMIT 5 ;
DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET tmpname = NULL;
OPEN cur1;
FETCH cur1 INTO tmpName;
WHILE ( tmpname IS NOT NULL) DO
/*自己的業務邏輯(我是把字符串相加)*/
SET tmpName = CONCAT(tmpName ," ") ;
SET temp_id = CONCAT(temp_id ,tmpName) ;
FETCH cur1 INTO tmpName;
END WHILE;
CLOSE cur1;
SELECT temp_id ;-- 打印結果
END
DELIMITER ;
2、Repeat方式：
DELIMITER
USE `ct1_test`
DROP PROCEDURE IF EXISTS `searchDate`
CREATE DEFINER=`greesj1b`@`%` PROCEDURE `searchRepeat`()
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE a VARCHAR(200) DEFAULT '';
DECLARE temp_id VARCHAR(1024) DEFAULT '' ;
DECLARE mycursor CURSOR FOR SELECT _id FROM `wp04_project` ORDER BY _id ASC LIMIT 5 ;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
OPEN mycursor;
REPEAT
FETCH mycursor INTO a;
IF NOT done THEN
SET temp_id=CONCAT(temp_id,a,' ');/*字符串相加,自己的業務邏輯*/
END IF;
UNTIL done END REPEAT;
CLOSE mycursor;
SELECT temp_id ;-- 打印結果
END$$
DELIMITER ;
3、Loop方式：
DELIMITER
USE `ct1_test`
DROP PROCEDURE IF EXISTS `searchLoop`
CREATE DEFINER=`greesj1b`@`%` PROCEDURE `searchLoop`()
BEGIN
DECLARE id INT;
DECLARE temp_id VARCHAR(1024) DEFAULT '' ;
DECLARE done INT DEFAULT 0;
DECLARE cur1 CURSOR FOR SELECT _id FROM `wp04_project` ORDER BY _id ASC LIMIT 5 ;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
OPEN cur1;
emp_loop: LOOP
FETCH cur1 INTO id;
IF done=1 THEN
LEAVE emp_loop;
END IF;
SET temp_id=CONCAT(temp_id,id,' ');/*字符串相加,自己的業務邏輯*/
END LOOP emp_loop;
CLOSE cur1;
SELECT temp_id ;-- 打印結果
END
DELIMITER ;
執行方法：CALL searchDate()
結果打印：100001 100002 100003 100004 100005