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摘要: Select字句在逻辑上是SQL语句最后进行处理的最后一步,所以,以下查询会发生错误: SELECT YEAR(OrderDate) AS OrderYear, COUNT(DISTINCT CustomerID) AS NumCusts FROM dbo.Orders GROUP BY Order 阅读全文
posted @ 2012-12-11 00:21 韩严重 阅读(78) 评论(0) 推荐(0) 编辑