Trying to update a field conditionally in SQL Stored Procedure - sql

Question

I have a procedure that populates two sets of application information into the same fields. First the fields are filled out with applicable accounts from group "A" and then the same process happens for group "B" accounts.
Most of the group B fields are filled in by a insert/select statement. However, the query to select "account number" is a little more complex and that is in an UPDATE statement. I will paste the code below but I cannot get it to properly update the rows (for group B) with account numbers, despite the fact the query works on its own outside the procedure (essentially, the account numbers do exist).
Any idea why? I tried adding a case statement to single out group B rows (the where clause is hardcoded for group B... e.g. clfcode = 3) but that didn't work. Let me know if you need more information. I haven't much experience with update statements in stored procedures.
update src
set account_key = case when src.clfcode = 3 and src.branch_key = 12 then a.account_key else src.account_key end
from #src_table src
inner join SDFDW_Landing.cu.FICS_ms_Investor_Loan l
on l.loan_id = src.application_number
left join dm.dim_product p
on p.product_key = src.product_key
left join (
Select Distinct t.PARENTACCOUNT, t.USERCHAR1 as loan_id
from SDFDW_Landing.dbo.tracking t
where t.TYPE = 1
and t.ProcessDate = #v_max_last_processed_date
and t.USERCHAR1 is not null
) t on t.loan_id = l.loan_id
left join dm.dim_account a
on t.PARENTACCOUNT = a.account_nkey
WHERE p.bdw_report_category = 'Mortgage'
and l.processdate = #v_max_last_processed_date

Answer 1

The join on a subquery might cause the issue. You could try to replace it with an apply and see if that helps.
update
src
set
account_key =
case
when
src.clfcode = 3
and src.branch_key = 12
then
a.account_key
else
src.account_key
end
from
#src_table src
inner join
SDFDW_Landing.cu.FICS_ms_Investor_Loan l
on l.loan_id = src.application_number
left join
dm.dim_product p
on p.product_key = src.product_key
outer apply (
Select
acc.*
from
dm.dim_account acc
inner join
SDFDW_Landing.dbo.tracking t
on acc.account_nkey = t.parentaccount
where
t.TYPE = 1
and t.ProcessDate = #v_max_last_processed_date
and t.USERCHAR1 is not null
and t.loan_id = l.loan_id
) a
WHERE
p.bdw_report_category = 'Mortgage'
and l.processdate = #v_max_last_processed_date
alternatively since you are already within a stored procedure, I'd populate a temp table with the data from your subquery and simply join on that temp table from your update statement.