# UNION Clause

The `UNION` clause allows the results of two queries to be combined. The second query is surrounded by parentheses.

    select * from java.lang.String union (select * from java.lang.StringBuilder)

The two queries must match in the number of columns in the select clause.

    SELECT s, s.value, s.hash FROM java.lang.String s  UNION (SELECT b, b.value, "dummy" FROM java.lang.StringBuilder b )

Parent topic: OQL Syntax