[sqlite] Fastest way to find whether at least one row has a certain column value

[Clemens Ladisch]

Tim Streater wrote:
> On 05 Mar 2016 at 13:05, Clemens Ladisch <clemens at ladisch.de> wrote:
>> But why do you want to determine the number of rows in the first place?
>
> In my case I want to know whether at least one row exists that has a certain 
> column which has a given value. At the minute I do this:
>
>   select count(*) from mytable where status=1 limit 1;
>
> Would this:
>
>   select count(*) from (select status from mytable where status=1 limit 1);
>
> or some other query be faster. Really, I'd like SQLite to stop after finding 
> one row.

So you want to know whether such a row exists? Then ask for that:

  SELECT EXISTS (select status from mytable where status=1);

This returns a boolean value.


Regards,
Clemens