SELECT DISTINCT 在 SQL 服务器 2014 中的一列上

Question

In SQL Sever 2014 , I have a table like this:

tag_id        prd_id        prod_nm
--------------------------------------
1               1           apple
2               1           apple
3               1           apple
4               2           banana
5               2           banana
6               3           tomato
7               3           tomato
8               4           cabbage
9               5           melon

And I want to get the highest tag_id for each product.

tag_id   prd_id     prod_nm
------------------------------
3       1           apple
5       2           banana
7       3           tomato
8       4           cabbage
9       5           melon

I used Distinct , Top , Order by but it isn't working. How can I get this result?

Answer 1

You need the max() aggregate function but then you have to do a group by to group the result-set by the other columns:

SELECT max(tag_id) AS tag_id, prd_id, prod_nm 
FROM table 
GROUP BY prd_id, prod_nm

Answer 2

You can use max with group by

select max(tag_id)tag_id,prd_id,prod_nm 
from mytable 
group by prd_id,prod_nm