??????????????????????????????????????????????
????1???κ????????? UPDATE??INSERT ?? DELETE ?????????????????????С?
????2??????б??????б??????????????е?????????????????κ????????????Щ?н?????????????????·????
????1??????????AVG??COUNT??SUM??MIN??MAX??GROUPING??STDEV??STDEVP??VAR ?? VARP??
????2???????????????????е?????м?????С???ü???????? UNION??UNION ALL??CROSSJOIN??EXCEPT ?? INTERSECT ?γ???н?????????????????????
????3?????????в??? GROUP BY??HAVING ?? DISTINCT ???????
????4??TOP ??????? select_statement ?е??κ?λ????????? WITH CHECK OPTION ????????á?
??????????????????????? FROM ????е??κ???????????????????????????????????￡??????????????????????????????嵽???????????