[Solved] Identify the error in this query:SELECT employee_id, LAST_VALUE(salary) OVER (ORDER BY employee_id) AS last_sal FROM employees; | SQL

SQL - Advanced Window Functions

Identify the error in this query:

SELECT employee_id, LAST_VALUE(salary) OVER (ORDER BY employee_id) AS last_sal FROM employees;

ALAST_VALUE needs a frame clause to get correct last value

BMissing PARTITION BY clause causes error

CORDER BY cannot be used inside OVER()

Dsalary column must be aggregated with GROUP BY

Step-by-Step Solution

Solution:

Step 1: Check LAST_VALUE default behavior
By default, LAST_VALUE looks only up to current row, so it may not return the true last value.
Step 2: Add frame clause to fix
Adding ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING makes LAST_VALUE consider all rows.
Final Answer:
LAST_VALUE needs a frame clause to get correct last value -> Option A
Quick Check:
LAST_VALUE without frame returns wrong last row [OK]

Quick Trick: Add full frame to LAST_VALUE for correct last row [OK]

Common Mistakes:

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