对SQL Server上的子查询求和

Question

我有一个查询内部的一些子查询,我想添加一个求和查询来总结它们.
我怎样才能做到这一点？

例:

Id,
(SELECT COUNT(*) FROM table1 LEFT JOIN table2 on ...) as col1,
(SELECT COUNT(*) FROM table3 LEFT JOIN table4 on ...) as col2,
** Sum of both col1 and col2 here **

Answer 1

试试这个:

SELECT ID, col1, col2, [Total] = (col1 + col2)
FROM (
    SELECT Id,
    (SELECT COUNT(*) FROM table1 LEFT JOIN table2 on ...) as col1,
    (SELECT COUNT(*) FROM table3 LEFT JOIN table4 on ...) as col2
    FROM [TABLE]) T

希望有所帮助.