Support UNION function in BigQuery SQL

Question

BigQuery does not seem to have support for UNION yet: https://developers.google.com/bigquery/docs/query-reference

(I don't mean unioning tables together for the source. It has that.)

Is it coming soon?

Answer 1

If you want UNION so that you can combine query results, you can use subselects in BigQuery:

SELECT foo, bar 
FROM
  (SELECT integer(id) AS foo, string(title) AS bar 
   FROM publicdata:samples.wikipedia limit 10),
  (SELECT integer(year) AS foo, string(state) AS bar 
   FROM publicdata:samples.natality limit 10);

This is almost exactly equivalent to the SQL

SELECT id AS foo, title AS bar 
FROM publicdata:samples.wikipedia limit 10
UNION ALL
SELECT year AS foo, state AS bar 
FROM publicdata:samples.natality limit 10;

(note that if want SQL UNION and not UNION ALL this won't work)

Alternately, you could run two queries and append the result.