将所有类似的列加起来，其中列名称为一列，总计为另一列

Question

I have a table with some data similar to this:

col1 | col2
-----------
val1    1
val1    5
val1    7
val2    3
val2    1
val2    4
val3    8

What I would like is a query to produce something like this:

col1 | sum
----------
val1   13
val2   8
val3   8

I've tried doing this with complicated subqueries, but nothing is quite panning out. I think I may be overthinking it.

Answer 1

This should be all you need. This uses the aggregate SUM with a GROUP BY .

SELECT col1, SUM(col2)
FROM unicorns
GROUP BY col1

Answer 2

select col1, sum(col2) as sum from table group by col1

Answer 3

You just need to use the aggregate function sum() with a group by :

select col1, SUM(col2) total
from yourtable
group by col1

See SQL Fiddle with Demo

Answer 4

  Select col1, Sum(col2) sum
  From table
  Group By col1