SUM( SELECT a FROM tab WHERE b > 0);
这种语法不起作用(至少在sqlite中不起作用),所以我试图找出正确的语法。
SELECT SUM(a) FROM tab WHERE b > 0 GROUP BY (*); % nope SELECT SUM(a) FROM tab WHERE b > 0 GROUP BY (1); % nope
SELECT SUM(a) FROM tab WHERE b > 0 ?
SELECT SUM(a) FROM tab WHERE b > 0
SELECT SUM(a) FROM tab GROUP BY (b > 0) HAVING (b > 0);