MySQL 存储过程中的循环操作

MySQL 存储过程中的循环操作
使用光标执行循环操作
DROP PROCEDURE IF EXISTS sp_opr;
CREATE PROCEDURE sp_opr()
BEGIN


    DECLARE username CHAR(32) DEFAULT '';

    DECLARE PASSWORD varchar(128) DEFAULT 0;
   

    DECLARE _done INT DEFAULT 0;
    DECLARE _cur_appsers CURSOR FOR
        SELECT username,password FROM app_user;
    DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET _done = 1;
   
    OPEN _cur_appsers;

        REPEAT
          FETCH _cur_appsers INTO username, PASSWORD;
         
         
          IF NOT _done THEN
SELECT username;
          END IF;
         
        UNTIL _done END REPEAT;

    CLOSE _cur_appsers;
END;

call sp_opr();