SQL Join with subquery

Question

Want to create a query that will join 3 tables together (a, b, c). Then update a specific cell in b.1, based on the subtraction of two specific cells in table b( b.2 - b.3).

Any help would be appreciated.

Answer 1

UPDATE b
SET b.c1 = b.c2 - b.c3
FROM a 
    JOIN b ON ...
    JOIN c ON ...