UPDATE with several records from another table

Question

I have a table T1 where I have the ID.
I have a table T2 where you take the ID_T1(Foreign Key) of T1.
I have a table T3 where you take the ID_T1(Foreign Key) of T1 and the ID_T2(Foreign Key) of T2.

On the table T3, the Ids of T1 are set, however, to T3 I created after these records were entered, IE, are with the column records ID_T2 to NULL. Is there any way I can make some UPDATE in T3, passing all the Ids of the T2 in the right way?

Below is the code I’m trying:

UPDATE  T3 
SET     T3.ID_T2 =  (
                        SELECT      T2.ID 
                        FROM        T2 
                        INNER JOIN  T3 ON T2.ID_T1 = T3.ID_T1
                    ) 
WHERE   T3.ID_T1 =  (
                        SELECT      T1.ID 
                        FROM        T1 
                        INNER JOIN  T3 ON T3.ID_T1 = T1.ID 
                        INNER JOIN  T2 ON T2.ID_T1 = T3.ID_T1
                    )

In SQL Server 2008.

Answer 1

This query can solve your problem:

UPDATE      T3 
SET         T3.ID_T2 = T2.ID
FROM        T3
INNER JOIN  T1 ON T1.ID     = T3.ID_T1
INNER JOIN  T2 ON T2.ID_T1  = T1.ID

What it does is basically update the ID_T2 with the ID from the table T2, which in turn is associated with the table T1 for ID_T1.