[Solved] Identify the error in this query:SELECT id FROM customers WHERE EXISTS SELECT * FROM orders WHERE orders.customer_id = customers.id; | PostgreSQL

PostgreSQL - Subqueries in PostgreSQL

Identify the error in this query:

SELECT id FROM customers WHERE EXISTS SELECT * FROM orders WHERE orders.customer_id = customers.id;

AIncorrect table alias usage

BUsing SELECT * instead of SELECT 1 in EXISTS

CMissing WHERE clause in subquery

DMissing parentheses around the subquery after EXISTS

Step-by-Step Solution

Solution:

Step 1: Check EXISTS syntax
The EXISTS keyword must be followed by a subquery enclosed in parentheses.
Step 2: Identify the error in the query
The query misses parentheses around the subquery, causing a syntax error.
Final Answer:
Missing parentheses around the subquery after EXISTS -> Option D
Quick Check:
EXISTS requires parentheses around subquery [OK]

Quick Trick: Always put parentheses after EXISTS [OK]

Common Mistakes:

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Identify the error in this query: