MySQL update table based on another tables value

Question

I have a two tables,

Here is my first table,

ID      SUBST_ID        CREATED_ID
1       031938          TEST123
2       930111          COOL123
3             


        

Answer 1

I think this should work

UPDATE secondTable
JOIN firsTable ON secondTable.SERIAL_ID = firsTable.SUBST_ID
SET BRANCH_ID = CREATED_ID