I have to update a field with a value which is returned by a join of 3 tables.
Example:
select
im.itemid
,im.sku as iSku
,gm.SKU as GSKU
You can specify additional tables used in determining how and what to update with the "FROM " clause in the UPDATE statement, like this:
update item_master
set mf_item_number = (some value)
from
group_master as gm
join Manufacturar_Master as mm ON ........
where
.... (your conditions here)
In the WHERE clause, you need to provide the conditions and join operations to bind these tables together.
Marc