[sqlite] Behaviour when subquery behind comparison operator in where-clause returns empty result

[James K. Lowden]

On Wed, 18 Feb 2015 08:55:37 +0100
gunnar <gharms at hiqinvest.nl> wrote:

instead of 

> SELECT *
> FROM ordercallback
> WHERE account=@ACCOUNT
>    AND cb_seq_num>(
>      SELECT cb_seq_num
>      FROM ordercallback
>      WHERE cb_uuid=@CBUUID);

SELECT *
FROM ordercallback ocb
WHERE account=@ACCOUNT
   AND exists (
     SELECT 1 
     FROM ordercallback
     WHERE cb_uuid=@CBUUID
        and ocb.cb_seq_num > cb_seq_num );

No union, no limit, no order.  Just existential quantification.  :-)

--jkl