Which Transact-SQL statement should you run?

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You have a database that contains tables named Customer_CRMSystem and Customer_HRSystem. Both tables use the following structure:

The tables include the following records:

Customer_CRMSystem

Customer_HRSystem

Records that contain null values for CustomerCode can be uniquely identified by CustomerName. You need to display customers who appear in both tables and have a proper CustomerCode.

Which Transact-SQL statement should you run?
A .


B .

C .

D .

E .

View Answer

Answer: A

Explanation:

When there are null values in the columns of the tables being joined, the null values do not match each other. The presence of null values in a column from one of the tables being joined can be returned only by using an outer join (unless the WHERE clause excludes null values).

References: https://technet.microsoft.com/en-us/library/ms190409(v=sql.105).aspx