Home  >  Article  >  Database  >  How to traverse cursor in mysql stored procedure

How to traverse cursor in mysql stored procedure

coldplay.xixi
coldplay.xixiOriginal
2020-10-28 14:51:433227browse

The method of cursor traversal in mysql stored procedure: first take the value and take multiple fields; then traverse the data end flag and bind the end flag to the cursor. The code is [DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;].

How to traverse cursor in mysql stored procedure

Method of cursor traversal in mysql stored procedure:

CREATE DEFINER=`root`@`%` PROCEDURE `updStatus`()
BEGIN
DECLARE startTime DATETIME;
DECLARE endTime DATETIME;
DECLARE curTime DATETIME;
DECLARE id VARCHAR(36); 
DECLARE estatus VARCHAR(4); 
-- 遍历数据结束标志
    DECLARE done INT DEFAULT FALSE;
    -- 游标
    DECLARE examIds CURSOR FOR SELECT EXAM_ID FROM t_exam WHERE EXAM_STATUS = 1 or EXAM_STATUS = 2;
    -- 将结束标志绑定到游标
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN  examIds;     
    -- 遍历
    read_loop: LOOP
-- 取值 取多个字段
FETCH  NEXT from examIds INTO id;
IF done THEN
LEAVE read_loop;
END IF;
SELECT EXAM_STATUS INTO estatus FROM t_exam WHERE EXAM_ID = id ;
IF estatus =1 THEN
SELECT NOW() INTO curTime;
SELECT EXAM_START_TIME INTO startTime  from t_exam WHERE EXAM_ID = id ;
SELECT EXAM_END_TIME INTO endTime  from t_exam WHERE EXAM_ID = id ;
IF curTime >= startTime AND endTime > curTime  THEN
UPDATE t_exam SET EXAM_STATUS = 2 WHERE EXAM_ID = id;
ELSEIF curTime >= endTime THEN
UPDATE t_exam SET EXAM_STATUS = 3 WHERE EXAM_ID = id;
END IF;
ELSE
SELECT NOW() INTO curTime;
SELECT EXAM_END_TIME INTO endTime  from t_exam WHERE EXAM_ID = id ;
IF curTime >= endTime THEN
UPDATE t_exam SET EXAM_STATUS = 3 WHERE EXAM_ID = id;
END IF;
END IF;
    END LOOP;
 
    CLOSE examIds;
END

More related free Learning recommendation: mysql tutorial(video)

The above is the detailed content of How to traverse cursor in mysql stored procedure. For more information, please follow other related articles on the PHP Chinese website!

Statement:
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn