[Solved] Identify the issue in this function:CREATE FUNCTION get_colors() RETURNS SETOF text AS $ BEGIN RETURN QUERY SELECT color FROM palette; RETURN NEXT 'extra'; END; $ LANGUAGE plpgsql; | PostgreSQL

PostgreSQL - Advanced PL/pgSQL

Identify the issue in this function:

CREATE FUNCTION get_colors() RETURNS SETOF text AS $$ BEGIN RETURN QUERY SELECT color FROM palette; RETURN NEXT 'extra'; END; $$ LANGUAGE plpgsql;

AThe function must return a single value, not SETOF.

BRETURN QUERY cannot be used with text data types.

CRETURN NEXT must be used before RETURN QUERY.

DThe function has unreachable code after RETURN QUERY.

Step-by-Step Solution

Solution:

Step 1: Understand RETURN QUERY
RETURN QUERY returns all rows and continues execution; it does not exit the function immediately.
Step 2: Check code after RETURN QUERY
RETURN NEXT 'extra' is reachable and will add an extra row after the query results.
Step 3: Identify problem
There is no unreachable code; the function returns all rows from SELECT plus one extra row.
Final Answer:
The function has no unreachable code; the RETURN NEXT after RETURN QUERY adds an extra row. -> Option D is incorrect

Quick Trick: RETURN QUERY does not exit function; code after it runs [OK]

Common Mistakes:

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Identify the issue in this function: