UPDATE with Subqueries (WHERE/FROM) - tsql

Question

I am attempting update a Yes/No field (Sealed) in a table called [Assets] from a subquery.
The subquery results contain the ID from [Assets] and the desired result of the field to be updated.
I have tried a few options, including WHERE or FROM clauses, but can't achieve the appropriate result.
Below is the basic Update statement and the subquery. Any advice is greatly appreciated.
UPDATE [Assets] SET Sealed = IsSealed
SELECT y.Asset AS Asset,
IIF(y.TotalSeals>0,Yes,No) AS IsSealed
FROM (
SELECT x.Asset,
SUM(IIF(x.BOMTypes="Seal",1,0)) AS BOMSeals,
SUM(IIF(x.MatMovTypes="Seal",1,0)) AS MMSeals,
SUM(IIF(x.POTypes="Seal",1,0)) AS POSeals,
(BOMSeals + MMSeals + POSeals) AS TotalSeals
FROM (
SELECT [Data - Assets].ID AS Asset,
[Data - Inventory].Type AS BOMTypes,
NULL AS MatMovTypes, NULL AS POTypes, NULL AS TotalSeals
FROM [Data - Inventory] INNER JOIN ([Data - Assets] INNER JOIN [Data - BOM]
ON [Data - Assets].ID = [Data - BOM].Asset)
ON [Data - Inventory].ID = [Data - BOM].Component
UNION ALL
SELECT [Data - Assets].ID AS Asset, NULL AS BOMTypes,
[Data - Inventory].Type AS MatMovTypes,
NULL AS POTypes, NULL AS TotalSeals
FROM ([Data - Assets] INNER JOIN [Data - WO]
ON [Data - Assets].ID = [Data - WO].Asset)
INNER JOIN ([Data - Inventory] INNER JOIN [Data - MatMov]
ON [Data - Inventory].ID = [Data - MatMov].Component)
ON [Data - WO].ID = [Data - MatMov].WorkOrder
UNION ALL
SELECT [Data - Assets].ID AS Asset,
NULL AS BOMTypes, NULL AS MatMovTypes,
[Data - Inventory].Type AS POTypes, NULL AS TotalSeals
FROM ([Data - Assets] INNER JOIN [Data - WO]
ON [Data - Assets].ID = [Data - WO].Asset)
INNER JOIN ([Data - Inventory] INNER JOIN [Data - PO]
ON [Data - Inventory].ID = [Data - PO].Component)
ON [Data - WO].ID = [Data - PO].WorkOrder
) AS x
GROUP BY x.Asset
) AS y;

Answer 1

Assuming that your table Assets contains a field Asset which corresponds to the y.Asset column in your subquery, then I would suggest the following:
update assets a inner join
(
select y.asset, iif(y.totalseals > 0, Yes, No) as issealed
from
(
***TLDR
) y
) t on a.asset = t.asset
set a.sealed = t.issealed
This assumes that your subquery does not contain any form of aggregation, else the query will not be updateable.
If your subquery includes aggregation, you could use a domain aggregate function, such as DCount or DSum (depending on the operations performed by your subquery).