Complex Update Question

Question

I have 2 tables a and b. Both tables have columns have the same primary keys. How would I go about updating a subset of the rows of column a from a column in column b?
Update (select * from a inner join b on a.id b.id where b.some_column=some_value)
set a.some_other_column=b.some_other_column
where a.some_other_column_2=some_other_value;
Problem is, this statement is not a valid SQL Statement. Could anyone help me please?
I hope the question is clear....

Answer 1

I think the SELECT * is fine, at least, it works with a straight select. Although, it is bad practice to do that. You do need to have an operator of some kind in the join condition. Something like:
UPDATE (SELECT *
        FROM a INNER JOIN b ON a.id = b.id
        WHERE b.some_column=some_value)
SET a.some_other_column = b.some_other_column
WHERE a.some_other_column_2 = some_other_value;TTFN
John