很難爲我構建主題名稱。但是我可以告訴一個例子:如何從同一表中優化幾個「WHERE(Select ....)= value」
WHERE (SELECT [ID_Line] FROM [Event] WHERE [Event].[Name] = [A].[Col]) = 2
AND (SELECT [DataType] FROM [Event] WHERE [Event].[Name] = [A].[Col]) = 2
在這裏,我處理2個查詢時,我真的很需要類似的東西:
WHERE (SELECT [ID_Line],[DataType] FROM [Event] WHERE [Event].[Name] = [A].[Col]) = 2,2
但SQL不與元組的工作,所以我必須做出Inner Join here?
什麼RDBMS請? – gbn 2011-05-13 10:06:40
@gbn ms sql 2008 express – Cynede 2011-05-13 10:31:43