SELECT TOP 2 MAX Value Group By SQL

Question

I have the following table:

-----------------------------------------
xDate        xItem       xCount
-----------------------------------------
2018-01-01   A           100
2018-01-01   B           200
2018-01-01   D           500
2018-01-02   C           200
2018-01-02   E           800

I want to select TOP 2 value for each date on the MAX value of xCount field. So, the result should be:

-----------------------------------------
xDate        xItem      xCount
-----------------------------------------
2018-01-01   D          500
2018-01-01   B          200
2018-01-02   E          800
2018-01-02   C          200

Does anyone have an idea for this case?
Cheers,

Answer 1

You can try to use RANK window function, if there more the two row have same xCount then you want to get them all.

You can try to use dense_rank instead of RANK

SELECT xDate,xItem,xCount
FROM (
    SELECT *,RANK() OVER(PARTITION BY xDate ORDER BY xCount DESC) rn
    FROM T
) t1
WHERE t1.rn <= 2