多项选择题
A.DATEB.TIME [(p)][WITH TIME Z0NE]C.TINESTAMP[(p)][WITHOUT TIME ZONE]D.TIME [(p)][WITHDUT TIME ZONE]
A.拉伸B.相交C.转换D.旋转
A.RIGHI JOINB.CROSS JOINC.LEFI JOIND.FULL JOIN