[sqlite] Selecting total and not used in one query

[Simon Slavin]

On 12 Dec 2015, at 2:42pm, Cecil Westerhof <cldwesterhof at gmail.com> wrote:

>> SELECT
>>        (SELECT COUNT(*) FROM proverbs)  AS Total
>>    ,   (SELECT COUNT(*) FROM proverbs WHERE used IS NOT NULL) AS Used
>>    ,   (SELECT COUNT(*) FROM proverbs WHERE used IS NULL)     AS Free
>> 
> 
> ?That is what I am using now, but it is inefficient. This uses three scans
> instead of two.?

Do you have an index on the column 'used' ?

Simon.