如何查找表中每列的最大值？

Question

我刚刚找到了满足此要求的确切查询。
我想在每一列中找到最大值。

这是一个例子

A B C D
-------
0 3 4 1
4 1 5 3
5 9 6 7
7 2 1 6

结果应该是这样的：

A | B | C | D |
--------------
7 | 9 | 6 | 7 |

如果你可以帮助我，那会更有帮助吗？

Answer 1

SELECT MAX(A) max_a,
       MAX(B) max_b,
       MAX(C) max_c,
       MAX(D) max_d
  FROM tablename

Answer 2

select max(a) as A ,max(b) as B  , max(c) as C  , max(d) as D  from 
 tablename 

Answer 3

select max(A) as A, max(B) as B, max(C) as C, max(D) as D from my_table ;