如何将不同的计数查询放在一个 table 结果中

Question

如果我有这三个计数查询，例如：

第一个：

Select count(*)   as red
from A 

result = 10

第二个：

Select count(*)   as yellow
from B

result = 15

第三名：

Select count (*)  as green
from C

result = 20

如何使用 oracle 使结果像

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

像这样：

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