[Solved] Find the error in this query:SELECT product_type, COUNT(*) FILTER (status = 'available') AS available_count FROM inventory GROUP BY product_type; | PostgreSQL

PostgreSQL - Aggregate Functions and GROUP BY

Find the error in this query:

SELECT product_type,
       COUNT(*) FILTER (status = 'available') AS available_count
FROM inventory
GROUP BY product_type;

ACOUNT(*) cannot be used with FILTER clause.

BThe FILTER clause is missing the WHERE keyword inside parentheses.

CGROUP BY should include status column as well.

DThe alias 'available_count' is not allowed in this context.

Step-by-Step Solution

Solution:

Step 1: Check FILTER syntax
The FILTER clause requires the condition to be inside parentheses with a WHERE keyword: FILTER (WHERE condition).
Step 2: Analyze the query
The query uses FILTER (status = 'available') missing WHERE, which is a syntax error.
Step 3: Verify other options
COUNT(*) can be used with FILTER, GROUP BY does not need status here, and aliasing is allowed.
Final Answer:
The FILTER clause is missing the WHERE keyword inside parentheses. -> Option B
Quick Check:
FILTER requires WHERE keyword inside parentheses [OK]

Quick Trick: FILTER clause must include WHERE keyword inside parentheses [OK]

Common Mistakes:

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