PostgreSQL

How to Use Coalesce in PostgreSQL

Say you’re looking at a PostgreSQL integer column where some rows are null:

select
  day,
  tickets
from stats;
    day     | tickets
------------+-------
 2018-01-01 |     1
 2018-01-02 |   null
 2018-01-03 |     3

Instead of having that null, you might want that row to be 0. To do that, use the coalesce function, which returns the first non-null argument it’s passed:

select
  day,
  coalesce(tickets, 0)
from stats;
    day     | tickets
------------+-------
 2018-01-01 |     1
 2018-01-02 |     0
 2018-01-03 |     3