A select count(*) will return nothing rather than 0, if no rows pass the WHERE conditions.
Eg, load wikipedia.
select count(*) from wikipedia - returns 24433 (for me, in my load)
select count(*) from wikipedia where channel = 'abc' - returns nothing, not 0.
This is true running in the console, or using the API. There I get [{"EXPR$0":24433}] for the first query, and [] for the second.
A select count(*) will return nothing rather than 0, if no rows pass the WHERE conditions.
Eg, load wikipedia.
select count(*) from wikipedia- returns 24433 (for me, in my load)select count(*) from wikipedia where channel = 'abc'- returns nothing, not 0.This is true running in the console, or using the API. There I get
[{"EXPR$0":24433}]for the first query, and[]for the second.