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摘要： --演示数据IF OBJECT_ID('tempdb..#A') IS NOT NULL DROP TABLE #AGOCREATE TABLE #A (A_ID INT,A_COL INT)INSERT #ASELECT 1 , 1 UNION ALLSELECT 2 , NULL UNION ALLSELECT 3 , 1 UNION ALLSELECT 3 , 2 UNION ALLSELECT 4 , 1IF OBJECT_ID('tempdb..#B') IS NOT NULL DROP TABLE #AGOCREATE TABLE #B(B_ID I 阅读全文