You must write a statement that combines the first_name and last_name columns from the employees table as "last_name, first_name." Which two statements will do this?

Question

Options

• ASELECT last_name + ', ' + first_name FROM employees;
• BSELECT CONCAT_WS(', ',last_name,first_name) FROM employees;
• CSELECT GROUP_CONCAT(last_name, first_name) FROM employees;
• DSELECT last_name, ` , ',first_name FROM employees;
• ESELECT CONCAT(last name,', ',first_name) FROM employees;

• A
  13% (4)
• B
  77% (23)
• C
  7% (2)
• D
  3% (1)

Explanation

Options B and E are correct because both properly use string concatenation functions to combine columns in the required "last_name, first_name" format. CONCAT(last_name, ', ', first_name) explicitly joins the three pieces in order, while CONCAT_WS(', ', last_name, first_name) achieves the same result using a separator as its first argument - a cleaner option when joining many fields with the same delimiter.

Option A is wrong because + is the arithmetic addition operator in MySQL/standard SQL - it won't concatenate strings the way it does in SQL Server. Option C is wrong because GROUP_CONCAT is an aggregate function that merges values across rows, not across columns within a single row. Option D is wrong due to a syntax error - the mismatched backtick and quotes make it invalid, and the bare comma would return two separate columns rather than one combined string.

Memory tip: Think of CONCAT as "list everything to join," and CONCAT_WS as "set the separator once, then list the values" - the WS stands for With Separator. If you see GROUP_CONCAT, think grouping/aggregation, not column merging.

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