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SQL:union和union all的区别 union:对两个结果集进行并集操作,不包含重复行,同事进行默认规则进行排序 union all:对两个结果集进行并集操作,包含重复行,不进行排序 注: - 在对结果集进行排序时,排序(order by)只能放在最后 - union和union all可以一起使用,但最终结果是union的结果 效率 union all比union快,...
Dim cn As Object Dim rs As Object Dim strFile As String Dim strCon As String Dim strSQL As...
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