需要简单的sql解决方案

Question

SELECT distinct denomination, 
(SELECT count(com) from security where denomination = 200), 
(SELECT count(com) from security where denomination = 50), 
(SELECT count(com) from security where denomination = 1000), 
(SELECT count(com) from security where denomination = 100) from security; 

denomination | ?column? | ?column? | ?column? | ?column? 
--------------+----------+----------+----------+---------- 
      200 |  1 |  2 |  1 |  2 
      50 |  1 |  2 |  1 |  2 
      100 |  1 |  2 |  1 |  2 
     1000 |  1 |  2 |  1 |  2 

上面的代码打印上面的结果。那不是我想要的。我如何为每个面额值写出com的数量，以便在各个面额附近的单独列中出现？我希望它看起来像这样：

denomination | ?column? | 
--------------+----------+ 
      200 |  1 | 
      50 |  2 | 
      100 |  2 | 
     1000 |  1 | 

我确定答案很简单，我只是不能让我的思绪围绕它。

Answer 1

SELECT denomination, count(com) 
FROM security 
WHERE denomination IN (200, 50, 1000, 100) 
GROUP BY denomination;