试图在SQL中划分两个计数

Question

因此，我试图进行简单的划分，当然，SQL是超级合乎逻辑的，这使得它变得不可能。我想要做的是：

SELECT * FROM 
1 - ((SELECT COUNT(DISTINCT T.DID) FROM TGAMAZING T AS NUM) * 100 /
(SELECT COUNT(DISTINCT D.ID) FROM DIRECTORS D AS DENOM))

但我该怎么写这个SQL（Oracle）？

Answer 1

<强>的Oracle

SQL小提琴：http://sqlfiddle.com/#!4/34298/8

方法1：

SELECT 1 - (COUNT(DISTINCT DID) * 100 / COUNT(DISTINCT ID))
FROM TGAMAZING
cross join DIRECTORS;

方法2：

SELECT 1 - 
    (
        (SELECT COUNT(DISTINCT DID) FROM TGAMAZING) * 100 /
        (SELECT COUNT(DISTINCT ID) FROM DIRECTORS)
    )
FROM DUAL;

SQL Server

SQL小提琴：http://sqlfiddle.com/#!6/34298/3

方法1

SELECT 1 - (COUNT(DISTINCT DID) * 100.0 / COUNT(DISTINCT ID))
FROM TGAMAZING
cross join DIRECTORS;

方法2

SELECT 1 - 
    (
        (SELECT COUNT(DISTINCT DID) FROM TGAMAZING) * 100.0 /
        (SELECT COUNT(DISTINCT ID) FROM DIRECTORS)
    )

Answer 2

将计算写为字段并使用＆＃34; FROM DUAL＆＃34;，因为您不想查询任何表格。

SELECT  
  1 - ((SELECT COUNT(DISTINCT T.DID) FROM TGAMAZING T) * 100 /
  (SELECT COUNT(DISTINCT D.ID) FROM DIRECTORS D))
  AS RESULT
FROM DUAL

参考：Selecting from the DUAL Table。