[Solved] Identify the error in this query:SELECT customer_id, FIRST_VALUE(amount) OVER (PARTITION BY customer_id ORDER BY order_date ROWS UNBOUNDED PRECEDING) FROM orders; | PostgreSQL

PostgreSQL - Window Functions in PostgreSQL

Identify the error in this query:

SELECT customer_id, FIRST_VALUE(amount) OVER (PARTITION BY customer_id ORDER BY order_date ROWS UNBOUNDED PRECEDING) FROM orders;

ASyntax error due to missing parentheses

BMissing frame end in ROWS clause

CFIRST_VALUE cannot be used with PARTITION BY

DORDER BY cannot be used inside OVER clause

Step-by-Step Solution

Solution:

Step 1: Check frame clause syntax
The frame clause ROWS UNBOUNDED PRECEDING is incomplete; it requires an end boundary like AND CURRENT ROW.
Step 2: Validate other parts
ORDER BY is valid in OVER, PARTITION BY is allowed, and parentheses are correct.
Final Answer:
Missing frame end in ROWS clause -> Option B
Quick Check:
Frame clause must have start and end [OK]

Quick Trick: ROWS frame needs start and end boundaries [OK]

Common Mistakes:

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