how to count certain distinct records using sql with conditions

Question

I have data that is structured like this:

ID   Location Flag1 Flag2 Flag3  Date
A    A1        0      1       0  01/01/2013
A    A2        1      0       0  01/02/2013
A    A2        1      0       0  01/02/2013
A    A3        1      0       0  01/03/2013
A    A3        0      1       0  01/03/2013

I need to count (among multiple IDs), the number of distinct Dates by distinct Locations with distinct Flags. The ideal outcome would look like this:

ID  Date         Count
A   01/01/2013   1
A   01/02/2013   1
A   01/03/2013   2

There are elements in the data that caused A with Location A2 to be distinct despite having the same Flag1 values but I don't care about those and want to roll up the data in the ideal outcome.

I've tried using this:

select count distinct ID, Location, Flag1, Flag2, Flag3, count (distinct
ID||Location||Date) as count 
group by ID, Location

It doesn't seem to be right.

Answer 1

Here's one way to do it. Simply get the distinct records in a subquery and then count and group the data.

SELECT Id, [Date], COUNT(*) AS cnt
FROM
(
    SELECT DISTINCT ID, Location, Flag1, Flag2, Flag3, [Date]
    FROM YourTable
) AS data
GROUP BY data.Id, data.[Date]