How to get Column Names list if row IS NOT NULL in PostgreSQL

Question

can i get 'colNew_name' from a select query like table below?

original table:

category_name | col1_name  | col2_name  | 
:------------ | :--------- | :----------|
postgres      | 1          | null       |
SAM           | null       | 1          |
MariaDB       | 1          | 1          |

result table:

category_name | col1_name  | col2_name  |      colNew_name   |
:------------ | :--------- | :----------| :------------------|
postgres      | 1          | null       |     col1_name      |
SAM           | null       | 1          |     col2_name      |
MariaDB       | 1          | 1          | col1_name,col2_name|

Answer 1

If your list of columns is small and fixed you could always do:

SELECT *, 
       CONCAT_WS(',', 
                 CASE WHEN col1_name IS NULL THEN NULL ELSE 'col1_name' END,
                 CASE WHEN col2_name IS NULL THEN NULL ELSE 'col2_name' END)
       AS "colNew_name"
FROM table1

See http://sqlfiddle.com/#!15/a88af8/2