SET QUOTED_IDENTIFIER ON和SET ANSI_NULLS ON

distinct是sqlserver的标识符，如果想以distinct为表时，在QUOTED_IDENTIFIER为off的情况下，是不能创建表名为distinct的表的，因为在QUOTED_IDENTIFIER为off情况下，sqlserver的标识符是不允许加引号的，所以在
SET QUOTED_IDENTIFIER  off的情况下，不管distinct加引号或不加引号或加双引号都是不可以的。
但是在 SET QUOTED_IDENTIFIER on 的情况下是可以把sqlserver的标识符加上双引号来创建以sqlserver标识符为表名的表，但是加单引号也是不可以的。

SET QUOTED_IDENTIFIER OFF  
GO  
-- An attempt to create a table with a reserved keyword as a name  
-- should fail.  
CREATE TABLE "select" ("identity" INT IDENTITY NOT NULL, "order" INT NOT NULL);  
GO  
  
SET QUOTED_IDENTIFIER ON;  
GO  
  
-- Will succeed.  
CREATE TABLE "select" ("identity" INT IDENTITY NOT NULL, "order" INT NOT NULL);  
GO  
  
SELECT "identity","order"   
FROM "select"  
ORDER BY "order";  
GO  
  
DROP TABLE "SELECT";  
GO  
  
SET QUOTED_IDENTIFIER OFF;  
GO  

SET ANSI_NULLS ON