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 create a list of all unique customers that appear in either table.

Which Transact-SQL statement should you run?
A .

B .

C .

D .

E .


F .

G .

H .

View Answer

Answer: E

Explanation:

UNION combines the results of two or more queries into a single result set that includes all the rows that belong to all queries in the union. The UNION operation is different from using joins that combine columns from two tables.

Incorrect Answers:

F: UNION ALL incorporates all rows into the results. This includes duplicates. If not specified, duplicate rows are removed.

References: https://msdn.microsoft.com/en-us/library/ms180026.aspx