mysql if 用法 多个条件判断、字符串比较

use industry_finance;
DELIMITER //
 drop procedure if exists  updateCursor //   
 CREATE PROCEDURE updateCursor()
    BEGIN
         declare id varchar(20);
         declare month varchar(20);
         declare season varchar(20);
         declare cur1 CURSOR FOR SELECT ID_,month_ FROM t_industry_finance_instance;
     OPEN cur1;
         FETCH cur1 INTO id,month;
 WHILE (id is not null ) DO
if(month='01'||month='02'||month='03') THEN  set season='1';
end if;
if(month='04'||month='05'||month='06') THEN  set season='2';
end if;
if(month='07'||month='08'||month='09') THEN  set season='3';
end if;
if(month='10'||month='11'||month='12') THEN  set season='4';
end if;
 update t_industry_finance_instance  set  season_=season  where ID_=id;
  FETCH cur1 INTO id,month;
      END WHILE;           
    CLOSE cur1;
END;//
DELIMITER ;
call updateCursor();