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

以上代码打印上述结果。那不是我想要的。我如何写出每个面额值的com计数，以便它出现在各自面额附近的单独列中？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，我只是无法理解它。

Answer 1

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