when I do order on a counter_cache it returns nil objects first?
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29-01-2021 - |
Вопрос
I have owns_count counter_cache on my items model. When i do
Items.order("owns_cache DESC")
, it returns me objects that are nil before other results. If I do
"owns_cache ASC"
, it is correct.
What should I be doing?
Решение
How NULLs get ordered depends on the underlying database.
For PostgreSQL, you could do this:
Items.order("owns_cache DESC NULLS LAST")
For MySQL and SQLite:
Items.order("COALESCE(owns_cache, 0) DESC")
I think MySQL sorts NULLs at the bottom of a DESC ordering though so you might not need anything special there. This COALESCE approach will also work in PostgreSQL so this would be a portable solution that should give you consistent results everywhere.
If you wanted NULLs at the bottom on an ASC sort, you'd replace the 0
with something larger than the largest owns_cache
number.
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