How to generate sequence in postgresql

Question

when I execute following query.

select 30,60,90,120,150,180 from table

I get output given below

But my desire output like, Want out in only one column.

 sequence 
   30
   60
   90
   120
   150
   180

Is this possible?

Answer 1

Use UNION ALL that will work in all major RDBMSes

SELECT 30 "sequence" UNION ALL
SELECT 60 UNION ALL
SELECT 90 UNION ALL
SELECT 120 UNION ALL
SELECT 150 UNION ALL
SELECT 180

or use postgres' generate_series() function

SELECT * 
  FROM generate_series(30, 180, 30) "sequence";

Output:

| SEQUENCE |
|----------|
|       30 |
|       60 |
|       90 |
|      120 |
|      150 |
|      180 |

Here is SQLFIddle demo for both queries