Aggregate function in an SQL update query?

Question

I\'m trying to set the value in one table to the sum of the values in another table. Something along these lines:

UPDATE table1
SET field1 = SUM(table2.fiel         


        

Answer 1

You can also use CTE like below.

;WITH t2 AS (
    SELECT field3, SUM(field2) AS field2
    FROM table2
    GROUP BY field3
)
UPDATE table1
SET table1.field1 = t2.field2
FROM table1
INNER JOIN t2 ON table1.field3 = t2.field3