Question

I have tables A,B

A holds a NETWORK_ID, column and a SUBSCRIPTION_ID

B holds a SUBSCRIPTION_ID(foreign key) and a CARD_ID column

I am going to need to update only CARD_ID (say value 50) to all instances of rows of B that have the NETWORK_ID of say 39.

So if this was one table that would have been easy, just:

update table set CARD_ID=50 where NETWORK_ID=39;

But how do I go about this here ?

Answer 1

Try this

UPDATE tableA A, tableB B
  SET B.CARD_ID = 50
  WHERE A.SUBSCRIPTION_ID = B.SUBSCRIPTION_ID
    AND A.NETWORK_ID = 39