How to Compare Two Values When One Is Null in PostgreSQL
Imagine you're comparing two PostgreSQL columns and you want to know how many rows are different. No problem, you think:
select count(1)
from items
where width != height;
Not so fast. If some of the widths or heights are null, they won't be counted! Surely that wasn't your intention. That's where is distinct from
comes into play:
select count(1)
from items
where width is distinct from height;
Now, your count will be "null aware" and you'll get the result you want 💥
Previous
How to Use CoalesceReal-time SQL collaboration is here
Get started with PopSQL and PostgreSQL in minutes