例子: ( R, u7 l" @( Q' h; CSELECT (SELECT SUM(...) FROM ...) as turnover, (SELECT SUM(...) FROM ...) as cost, turnover - cost as profit确定这是无效的(至少在Postgres有效)但是如何在不重写的情况下在查询中达到同样的效果呢? , M* B4 w; {& P0 R y1 c' a1 f . X" X& }5 n" Q( o% u0 V. E5 w解决方案: , v! y! y0 `% r" b 像这样: ' {. R. \, |- m) m* X+ b& T: ~SELECT turnover, cost, turnover - cost as profitfrom ( (SELECT SUM(...) FROM ...) as turnover, (SELECT SUM(...) FROM ...) as cost ) as partial_sums