SQL noob trying to do update query with join - mysql

Question

I’m trying to run an update query which I’ll run daily, unfortuntately I suck at SQL and have no clue what to do with the join functions. I keep getting invalid group error. I took the table names out
Managed to narrow down the issue (this is in SQLYog btw)
UPDATE CMCDAR
SET cmcdar.effective_exposure_in_global_currency = (mcdar.A_Rbalance - SUM(CASE
WHEN eps.fk_account_id = '90059' AND eps.sent_to_erp = '0' THEN (eps.transaction_amount) ELSE 0 END))
FROM eps
JOIN cmcdar ON eps.fk_customer_map_id = cmcdar.fk_customer_map_id
JOIN mcdar ON eps.fk_customer_map_id = mcdar.fk_customer_map_id
JOIN mcar ON eps.fk_customer_map_id = mcar.pk_customer_map_id
WHERE cmcdar.is_deleted = 0
AND mcar.is_deleted = 0
AND mcdar.is_deleted = 0
GROUP BY eps.fk_customer_map_id;
without Group by it returns it all as one bi
g row, with group by it fails. Interestingly with + rather than - in the sum it seems to seperate it even without group by. Any workarounds for group by?

Answer 1

Your syntax is off - see here:SQL Update with a Join
UPDATE
t1
SET
t1.c1 = t2.c2,
t1.c2 = expression,
...
FROM
t1
[INNER | LEFT] JOIN t2 ON join_predicate
WHERE
where_predicate;

Answer 2

I would assume move the join into from clause.
UPDATE cmcdar
SET effective_exposure_in_global_currency = (mcdar.A_Rbalance - SUM(CASE WHEN eps.fk_account_id =
'90059' AND eps.sent_to_erp = '0' THEN (eps.transaction_amount) ELSE 0 END))
from cmcdar
JOIN eps ON cmcdar.fk_customer_map_id = eps.fk_customer_map_id
JOIN mcar ON cmcdar.fk_customer_map_id = mcar.pk_customer_map_id
JOIN mcdar ON cmcdar.fk_customer_map_id = mcdar.fk_customer_map_id
WHERE cmcdar.is_deleted = 0
AND cmcdar.fk_customer_map_id = eps.fk_customer_map_id
AND mcar.is_deleted = 0
AND mcdar.is_deleted = 0
AND cmcdar.fk_account_id = '90059'
AND mcdar.fk_account_id = '90059';