使用 Postgresql 将单行中的值拆分为多行

Question

With Postgresql I have the query:

select '1' , '2', '3';

with result

I would like to have next result:

column
1
2
3

How can I do that?

Answer 1

You could create an array and then use UNNEST():

SELECT UNNEST(ARRAY[1,2,3]);

Answer 2

You are looking for Unpivot , then you can try to use UNION ALL

select '1' column
UNION ALL
SELECT '2'
UNION ALL
SELECT '3'

or you can try to use JOIN LATERAL

SELECT s.*
FROM test t
JOIN LATERAL (VALUES(t.a),(t.b),(t.c)) s(column) ON TRUE

sqlfiddle

Answer 3

I prefer to use a table function for that:

SELECT CAST(i AS text) FROM generate_series(1, 3) AS i;