Combine two SELECT queries in PostgreSQL
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Use a CTE to reuse the result from a subquery in more than one SELECT
.
WITH cte AS (SELECT carto_id_key FROM table1 WHERE tag_id = 16)
SELECT carto_id_key
FROM cte
UNION ALL
SELECT t2.some_other_id_key
FROM cte
JOIN table2 t2 ON t2.carto_id_key = ctex.carto_id_key
You most probably want UNION ALL
instead of UNION
. Doesn't exclude duplicates and is faster this way.
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Comments
-
Bwyss almost 2 years
I would like to combine two select queries with
UNION
.
How can I use the result from the firstSELECT
in the secondSELECT
?(SELECT carto_id_key FROM table1 WHERE tag_id = 16) UNION (SELECT * FROM table2 WHERE carto_id_key = <the carto_id result from above> )