如何在一个表结果中放入不同的计数查询

Question

如果我有这三个计数查询，例如：

首先：

Select count(*)   as red
from A 

result = 10

第二

Select count(*)   as yellow
from B

result = 15

第三

Select count (*)  as green
from C

result = 20

如何使用oracle使结果像

一样

red      yellow      green
10         15          20

Answer 1

select (Select count(*) from a) red, (Select count(*) from b) yellow, (Select count(*) from b) green from dual;

Answer 2

类似的东西：

select * from (Select count(*) as red from A) as count_A
 ,(Select count(*)   as yellow from B) as count_B
 ,(Select count (*)  as green from C) as count_C