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
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