SQL UPDATE using two joined subqueries - sql

Question

I wrote a query that does an inner join of two subqueries. The first subquery has an alias of "SRC" and the other has an alias of "DEST". What I want to do is update some fields in the table NomineeActionLegislatorVoteDetail (part of DEST subquery) with values from the table Nominee_Committee_Vote (part of SRC subquery). It souds easy but I just cannot figure out how to do it. Does anyone have any suggestions? Any help would be appreciated.
Here is the query I wrote:
select *
from (
select ncv.*,
na.NomineeActionId,
l.LegislatorId
from ongoing..Nominee_Committee_Vote ncv
inner join azleg..NomineeAction na on
ncv.session_id = na.x_session_id and
ncv.committee_id = na.x_committee_id and
ncv.agency_id = na.x_agency_id and
ncv.position_id = na.x_position_id and
ncv.nominee_id = na.x_nominee_id and
ncv.received_date = na.x_received_date
inner join status..session s on
ncv.session_id = s.session_id
inner join azleg..Legislator l on
ncv.member_id = l.x_member_id and
s.legislature = l.LegislatureId
) SRC
inner join (
select votedetail.*
from azleg..NomineeActionLegislatorVoteDetail votedetail
inner join azleg..NomineeAction nom_action on
votedetail.NomineeActionId = nom_action.NomineeActionId
) DEST on
SRC.agency_id = DEST.x_agency_id and
SRC.position_id = DEST.x_position_id and
SRC.nominee_id = DEST.x_nominee_id and
SRC.received_date = DEST.x_received_date and
SRC.session_id = DEST.x_session_id and
SRC.committee_id = DEST.x_committee_id and
SRC.member_id = DEST.x_member_id
where SRC.NomineeActionId <> DEST.NomineeActionId
OR SRC.LegislatorId <> DEST.LegislatorId
OR SRC.Vote <> DEST.Vote

Answer 1

Can you insert the update in front of the sub queries
UPDATE NomineeActionLegislatorVoteDetail
SET NomineeActionLegislatorVoteDetail.COLUMNNAME = src.VALUE
--SubQueriesBelow
from
(select ncv.*, na.NomineeActionId, l.LegislatorId from ongoing..Nominee_Committee_Vote ncv
inner join azleg..NomineeAction na on
ncv.session_id = na.x_session_id and
ncv.committee_id = na.x_committee_id and
ncv.agency_id = na.x_agency_id and
ncv.position_id = na.x_position_id and
ncv.nominee_id = na.x_nominee_id and
ncv.received_date = na.x_received_date
inner join status..session s on
ncv.session_id = s.session_id
inner join azleg..Legislator l on
ncv.member_id = l.x_member_id and
s.legislature = l.LegislatureId) SRC
inner join
(select votedetail.* from azleg..NomineeActionLegislatorVoteDetail votedetail
inner join azleg..NomineeAction nom_action on
votedetail.NomineeActionId = nom_action.NomineeActionId) DEST on
SRC.agency_id = DEST.x_agency_id and
SRC.position_id = DEST.x_position_id and
SRC.nominee_id = DEST.x_nominee_id and
SRC.received_date = DEST.x_received_date and
SRC.session_id = DEST.x_session_id and
SRC.committee_id = DEST.x_committee_id and
SRC.member_id = DEST.x_member_id
where SRC.NomineeActionId <> DEST.NomineeActionId
OR SRC.LegislatorId <> DEST.LegislatorId
OR SRC.Vote <> DEST.Vote
It looks like the update is on a table in the sub query so it could be re factored to have one subquery

Answer 2

I've adjusted the lay-out of your query a bit to disclose better where subqueries start and end. In your DEST subquery, you join NomineeAction but you don't select any columns from it, so it only filters rows from NomineeActionLegislatorVoteDetail for which no NomineeAction exists. So really you wanna be updating and joining on columns from NomineeActionLegislatorVoteDetail exclusively. Based on that, I would write the update query like so:
update votedetail set
votedetail.SomeColumn = SomeValue,
votedetail.SomeOtherColumn = SomeOtherValue
from azleg..NomineeActionLegislatorVoteDetail votedetail
join azleg..NomineeAction nom_action on
votedetail.NomineeActionId = nom_action.NomineeActionId
join (
select ncv.*,
na.NomineeActionId,
l.LegislatorId
from ongoing..Nominee_Committee_Vote ncv
inner join azleg..NomineeAction na on
ncv.session_id = na.x_session_id and
ncv.committee_id = na.x_committee_id and
ncv.agency_id = na.x_agency_id and
ncv.position_id = na.x_position_id and
ncv.nominee_id = na.x_nominee_id and
ncv.received_date = na.x_received_date
inner join status..session s on
ncv.session_id = s.session_id
inner join azleg..Legislator l on
ncv.member_id = l.x_member_id and
s.legislature = l.LegislatureId
) SRC on
SRC.agency_id = votedetail.x_agency_id and
SRC.position_id = votedetail.x_position_id and
SRC.nominee_id = votedetail.x_nominee_id and
SRC.received_date = votedetail.x_received_date and
SRC.session_id = votedetail.x_session_id and
SRC.committee_id = votedetail.x_committee_id and
SRC.member_id = votedetail.x_member_id
where SRC.NomineeActionId <> votedetail.NomineeActionId
OR SRC.LegislatorId <> votedetail.LegislatorId
OR SRC.Vote <> votedetail.Vote