题目内容:
A.ItperformsamergejoinoftherowfromT2onlyifitdoesn’texistintheT1table.B.ItcreatesanaturaljoinoftablesT1andT2forallcolumnsthathavethesamename.
C.ItcreatesaCartesianproductoftableT1andtableT2forallcolumnsthathavethesamename.
D.ForeachrowfromT2,itupdatestherowifitexistswithintableT1,otherwiseitinsertstherowintoT1.
参考答案: