How to do multiple Left join with multiple ids with just 1 row (Top 1) on the right table - sql

Question

Im doing Multiple left joins on multiple Ids. Im trying to match only 1 result from the right table but not sure how to write the nested select when the join is on multiple IDs.
The last 2 left joins return more than 1 row even with the joins on multiple IDs (expected) however I'm only interested in matching ONE (Top 1) of the result on the right table.
I've already checked out other posts regarding left joins but none of them includes joining with multiple ids.
Basically I'm trying to get a list of operations from the Operation Table (Left Table) . Each operation has an identifier with the Type, Base ID, Lot ID, Split ID, Sub ID & Sequence No which lead to a unique operation. All the tables mentioned have each of these columns present.
However, the "Requirement" table "R" may have more than 1 row for each unique operation and I only need 1 requirement from it. Same is the case for the "Operation_Audit" table "OA".
I've only put 1 column for each table under the select for ease of reading.
Select
O.SETUP_HRS As [Setup Time], O.RUN_HRS As [Run Time],
OS.RESOURCE_ID As [Shop Resource],
WO.PART_ID As [Part ID / Assy],
P.DESCRIPTION As [Part / Assy Description],
WOV.DESCRIPTION As Description,
R.CLOSE_DATE As [Req Issue Date],
OA.RESULT_DETAIL As Reason
From OPERATION As O
Inner Join OPERATION_SCHED OS On
O.WORKORDER_TYPE = OS.WORKORDER_TYPE And
O.WORKORDER_BASE_ID = OS.WORKORDER_BASE_ID And
O.WORKORDER_LOT_ID = OS.WORKORDER_LOT_ID And
O.WORKORDER_SPLIT_ID = OS.WORKORDER_SPLIT_ID And
O.WORKORDER_SUB_ID = OS.WORKORDER_SUB_ID And
O.SEQUENCE_NO = OS.SEQUENCE_NO
Inner Join WORK_ORDER WO On
O.WORKORDER_TYPE = WO.[TYPE] And
O.WORKORDER_BASE_ID = WO.BASE_ID And
O.WORKORDER_LOT_ID = WO.LOT_ID And
O.WORKORDER_SPLIT_ID = WO.SPLIT_ID
Left Outer Join PART P On
P.ID = WO.PART_ID
Inner Join CR_WO_PART WOV On
O.WORKORDER_TYPE = WOV.[TYPE] And
O.WORKORDER_BASE_ID = WOV.BASE_ID And
O.WORKORDER_LOT_ID = WOV.LOT_ID And
O.WORKORDER_SPLIT_ID = WOV.SPLIT_ID And
O.WORKORDER_SUB_ID = WOV.SUB_ID
Left Outer Join REQUIREMENT R On
O.WORKORDER_TYPE = R.WORKORDER_TYPE And
O.WORKORDER_BASE_ID = R.WORKORDER_BASE_ID And
O.WORKORDER_LOT_ID = R.WORKORDER_LOT_ID And
O.WORKORDER_SPLIT_ID = R.WORKORDER_SPLIT_ID And
O.SEQUENCE_NO = R.OPERATION_SEQ_NO And
O.WORKORDER_SUB_ID = R.WORKORDER_SUB_ID
Left Outer Join OPERATION_AUDIT OA On
O.WORKORDER_TYPE = OA.WORKORDER_TYPE And
O.WORKORDER_BASE_ID = OA.WORKORDER_BASE_ID And
O.WORKORDER_LOT_ID = OA.WORKORDER_LOT_ID And
O.WORKORDER_SPLIT_ID = OA.WORKORDER_SPLIT_ID And
O.WORKORDER_SUB_ID = OA.WORKORDER_SUB_ID And
O.SEQUENCE_NO = OA.SEQUENCE_NO And
OA.RESULT = 'M'
Where
O.COMPLETED_QTY <= O.CALC_END_QTY And
WO.SUB_ID = '0' And
O.WORKORDER_TYPE = 'W' And
OS.SCHEDULE_ID = 'STANDARD' And
FilterCriteria = #FilterCriteria

Answer 1

I would create the queries that result in the desired one row being returned for each unique operation from tables R and OA. Then set those queries up as common table expressions (CTE). Then do your original query above (left is good enough, left outer not needed) but join to the single record CTE's instead of R and OA.