Question

我有两个问题：

SELECT SUM(DATALENGTH(Money)) / 1048576.0 from Money

SELECT SUM(DATALENGTH(Cc)) / 1048576.0 from CC

如果单独跑，他们会返回20和30。我想结合这些来得到50的结果。

这可以在一行中完成吗？而是分配查询1和2的两个变量值并添加它们？

Answer 1

执行此操作的标准方法是使用cross join：

select val1 + val2
from (SELECT SUM(DATALENGTH(Money)) / 1048576.0 as val1 from Money
     ) t1 cross join
     (SELECT SUM(DATALENGTH(Cc)) / 1048576.0 as val2 from CC
     ) t2

Answer 2

select sum(sm) as total_sum
from (
  SELECT SUM(DATALENGTH(Money)) / 1048576.0 as sm 
  from Money

  union all

  SELECT SUM(DATALENGTH(Cc)) / 1048576.0 
  from CC
) t

Answer 3

这应该可以解决问题：

SELECT 
(SUM(DATALENGTH(Money)) / 1048576.0) + SUM(DATALENGTH(Cc)) / 1048576.0
from Money, CC

Answer 4

我相信这会奏效：

Select 
   (SELECT SUM(DATALENGTH(Money)) / 1048576.0 from Money) 
 + (SELECT SUM(DATALENGTH(Cc)) / 1048576.0 from CC)

至少它在我的数据库引擎中。

Answer 5

SELECT SUM(S)
FROM (
    SELECT SUM(DATALENGTH(Money)) / 1048576.0 S from Money
    UNION ALL
    SELECT SUM(DATALENGTH(Cc)) / 1048576.0 from CC
) Q;

添加两个查询sql

5 个答案: