Unable to execute update query. Can't we use a query within a update query which also has joins?

Question

Below is the query:
UPDATE 
(select * from [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals as CFRQ
LEFT JOIN [HR_DEV_DM].[CFQ_TEST].t_Chg_Rsns as CHGRSNS
ON CFRQ.RecChangeID = CHGRSNS.Chg_ReasID)
INNER JOIN [HR_DEV_DM].[CFQ_TEST].t_Qt_Typs
ON [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.QuoteType = [HR_DEV_DM].[CFQ_TEST].t_Qt_Typs.Qt_Typ 
SET [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecKey = dbo.BuildRecordKey([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[ReferralCode], [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[RetentionID],
[HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[ClientFName],[HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[ClientLName], 
IIf([HR_DEV_DM].[CFQ_TEST].t_Qt_Typs.Qt_Grp='MOAT',[HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[QuotePolicyType],[HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[ClientZip]),
[HR_DEV_DM].[CFQ_TEST].[CFQ_Referrals].[QuoteType])
WHERE ((([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecProcessed)=0) 
AND (([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecChange)=Yes) 
AND (([HR_DEV_DM].[CFQ_TEST].t_Chg_Rsns.ImpactsRecKey)=Yes)) 
OR ((([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecKey) Is Null)) OR ((([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecKey)=''));
When I run this query, below are the errors I see:
Msg 102, Level 15, State 1, Line 2
Incorrect syntax near '('.
Msg 156, Level 15, State 1, Line 6
Incorrect syntax near the keyword 'INNER'.
Msg 102, Level 15, State 1, Line 14
Incorrect syntax near 'HR_DEV_DM'.
Msg 102, Level 15, State 1, Line 17
Incorrect syntax near 'HR_DEV_DM'.
Msg 102, Level 15, State 1, Line 17
Incorrect syntax near 'HR_DEV_DM'.
I don't see any problem with 'HR_DEV_DM'. Because,  I was able to run the below queries:
select * from [HR_DEV_DM].[CFQ_TEST].t_Chg_Rsns
select * from [HR_DEV_DM].[CFQ_TEST].t_Qt_Typs where Qt_Typ = 'Auto/Cycle'
select * from [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals where QuoteType = 'MOAT'
Please help.......

Answer 1

What you are trying to achieve is possible, it's just a matter of syntax.
UPDATE [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals
SET [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecKey = dbo.BuildRecordKey([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[ReferralCode], [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[RetentionID],
[HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[ClientFName],[HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[ClientLName],
IIf([HR_DEV_DM].[CFQ_TEST].t_Qt_Typs.Qt_Grp='MOAT',[HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[QuotePolicyType],[HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.[ClientZip]),
[HR_DEV_DM].[CFQ_TEST].[CFQ_Referrals].[QuoteType])
FROM
select * from [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals as CFRQ
LEFT JOIN [HR_DEV_DM].[CFQ_TEST].t_Chg_Rsns as CHGRSNS
ON CFRQ.RecChangeID = CHGRSNS.Chg_ReasID
INNER JOIN [HR_DEV_DM].[CFQ_TEST].t_Qt_Typs
ON [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.QuoteType = [HR_DEV_DM].[CFQ_TEST].t_Qt_Typs.Qt_Typ
WHERE ((([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecProcessed)=0)
AND (([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecChange)=Yes)
AND (([HR_DEV_DM].[CFQ_TEST].t_Chg_Rsns.ImpactsRecKey)=Yes))
OR ((([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecKey) Is Null)) OR ((([HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecKey)=''))) A
WHERE [HR_DEV_DM].[CFQ_TEST].CFQ_Referrals.RecChangeID = A.RecChangeID