SQLite inner join - update using values from another table

Question

This is quite easy and has been asked multiple times but I can\'t get it to work. The SQL query I think should work is:

    UPDATE table2
       SET dst.a =          


        

Answer 1

SQLITE does not support UPDATE with INNER JOIN nor do several other DB's. Inner Joins are nice and simple however it can be accomplished using just a UPDATE and a subquery select. By using a where clause and the 'IN' with a subquery and a additional subquery for the 'SET' the same result can always be accomplished. Below is how it's done.

UPDATE table2
  SET a = a + (select a from table1 where table1.f = table2.f),
       b = b + (select b from table1 where table1.f = table2.f),
       c = c + (select c from table1 where table1.f = table2.f),
       d = d + (select d from table1 where table1.f = table2.f),
       e = e + (select e from table1 where table1.f = table2.f)
  WHERE RowId IN (Select table2.RowId from table1 where table1.f = table2.f)