SQL - Guess the output

Which statement(s) execute successfully or give error.

-- Statement 1 --

SELECT SYSOBJECTS.Name, SYSOBJECTS.Xtype, SYSOBJECTS.crdate, SYSOBJECTS.refdate

FROM SYSOBJECTS

GO

-- Statement 2 --

SELECT Name, Xtype, crdate, refdate

FROM SYSOBJECTS AS OBJ

GO

-- Statement 3 --

SELECT OBJ.Name, OBJ.Xtype, OBJ.crdate, OBJ.refdate

FROM SYSOBJECTS AS OBJ

GO

-- Statement 4 --

SELECT SYSOBJECTS.Name, SYSOBJECTS.Xtype, SYSOBJECTS.crdate, SYSOBJECTS.refdate

FROM SYSOBJECTS AS OBJ

GO

-- Statement 5 --

SELECT SYSOBJECTS.Name, OBJ.Xtype, OBJ.crdate, SYSOBJECTS.refdate

FROM SYSOBJECTS AS OBJ

GO

 

Answer: Statement 1 – Successful, Statement 2 – Successful, Statement 3 – Successful, Statement 4 – Error, Statement 5 – Error

Explanation: Using the table alias and the table name both in a single query in incorrect. If you are using table alias then you cannot use table name for reference in that query. You need to use the alias for reference.