SET two variables in SELECT statement - MySQL - mysql

Question

I am using below code which is executing in mysql but giving error while hitting through java program as java program cannot read semicolons ... for java these are 3 statements . I need to execute this query ( setting both variable and then selecting in one query):
set #row_number:=0;set #PROMOTION_ID_NO:='';
SELECT
#row_number:=CASE
WHEN #PROMOTION_ID_NO=PD.PROMOTION_ID THEN #row_number + 1
ELSE 1
END AS SEQ,
#PROMOTION_ID_NO:=PD.PROMOTION_ID AS PROMOTION_ID,
PD.CONDITION_CODE,
PM.PROMOTION_code,
PD.CONDITION_TYPE
FROM
POS_PROMOTION_DISCOUNT PD , POS_PROMOTION_MASTER PM WHERE
PD.PROMOTION_ID = PM.PROMOTION_ID
AND PD.STORE_NO = 'G121';

Answer 1

You can move the SET statement(s) to a separate Derived Table, and do a CROSS JOIN of that table with the other table(s).
Please don't use Old comma based Implicit joins and use Modern Explicit Join based syntax. I have changed to use JOIN .. ON instead.
Try the following:
SELECT
#row_number:=CASE
WHEN #PROMOTION_ID_NO=PD.PROMOTION_ID THEN #row_number + 1
ELSE 1
END AS SEQ,
#PROMOTION_ID_NO:=PD.PROMOTION_ID AS PROMOTION_ID,
PD.CONDITION_CODE,
PM.PROMOTION_code,
PD.CONDITION_TYPE
FROM
POS_PROMOTION_DISCOUNT PD
JOIN POS_PROMOTION_MASTER PM ON PD.PROMOTION_ID = PM.PROMOTION_ID
CROSS JOIN (SELECT row_number:=0, #PROMOTION_ID_NO:='') AS user_init
WHERE
PD.STORE_NO = 'G121';