I think the equivalent 'group by' is..
SELECT NCTags.NCTagID, NCTags.CreateDate, first(NCTags.Description) as TagsDesc
FROM NCDiscrepancies INNER JOIN NCTags ON NCDiscrepancies.NCTagID = NCTags.NCTagID
WHERE (DateValue([NCTags].[createDate])>=Date()-7) AND (NCTags.Description Like "*Rapid*")
Group By NCTags.NCTagID, NCTags.CreateDate;