SQL - how to count unique combination of columns

Question

I\'m not sure if this is possible but I want to count the number of unique value in a table. I know to count the number of unique folderIDs I do:

select count(f         


        

Answer 1

i think you can try to group the select statement with folder id

eg.

i have a table

folderid userid

1 11

1 11

2 12

2 12

3 13

3 13

Query is

select count(folderid) from testtable group by folderid, userid