SELECT
COUNT_BIG(DISTINCT C.CreationDate),
COUNT_BIG(DISTINCT C.PostId),
COUNT_BIG(DISTINCT C.Score),
COUNT_BIG(DISTINCT C.UserId)
FROM dbo.Comments AS C;
SELECT
APPROX_COUNT_DISTINCT(C.CreationDate),
APPROX_COUNT_DISTINCT(C.PostId),
APPROX_COUNT_DISTINCT(C.Score),
APPROX_COUNT_DISTINCT(C.UserId)
FROM dbo.Comments AS C;