除了ID列之外，如何合并和计算相同的MySQL行？

Question

我希望能够合并行，并找出除ID之外的相同数量。例如，如果我要使用此表：

+---------+-----------+-----------+
|  ID     |  Col 1    |  Col 2    |
+---------+-----------+ ----------+
|  1      |  1        |  5        |
|  2      |  1        |  5        |
|  3      |  4        |  9        |
|  4      |  3        |  9        |
|  5      |  1        |  5        |
|  6      |  1        |  5        |
|  7      |  1        |  5        |
|  8      |  4        |  9        |
+---------+-----------+-----------+

它会变成：

+---------+-----------+-----------+---------+
|  ID     |  Col 1    |  Col 2    |  Count  |
+---------+-----------+ ----------+---------+
|  1      |  1        |  5        | 5       |
|  2      |  4        |  9        | 2       |
|  3      |  3        |  9        | 1       |
+---------+-----------+-----------+---------+

对此的查询是什么？

Answer 1

在结果中的ID列旁边，对我来说看起来像你需要：

SELECT Col1, Col2, Count(Col1)
FROM myTable
GROUP BY Col1, Col2

Answer 2

select col1,col2,count(*) as `count`
from table
group by col1,col2