Which term describes a column produced by a calculation in a SELECT clause?

Which term describes a column produced by a calculation in a SELECT clause?

• A. derived column
• B. CAST
• C. COALESCE
• D. NOT

Answer: (A)

A derived column is the value produced by evaluating an expression in the SELECT clause. When you compute something from existing columns—like an arithmetic result or a concatenation—and give it an alias, that result becomes a derived (or computed) column in the query’s output. It isn’t stored in the table itself; it’s calculated each time the query runs. CAST, COALESCE, and NOT are different concepts used inside expressions. CAST converts a value’s data type, COALESCE picks the first non-null value, and NOT negates a boolean. They can appear in the expression that creates a derived column, but they themselves describe operations, not the column created by the calculation.

A derived column is the value produced by evaluating an expression in the SELECT clause. When you compute something from existing columns—like an arithmetic result or a concatenation—and give it an alias, that result becomes a derived (or computed) column in the query’s output. It isn’t stored in the table itself; it’s calculated each time the query runs.

CAST, COALESCE, and NOT are different concepts used inside expressions. CAST converts a value’s data type, COALESCE picks the first non-null value, and NOT negates a boolean. They can appear in the expression that creates a derived column, but they themselves describe operations, not the column created by the calculation.