[Solved] Find the issue in this query:SELECT name FROM employees e WHERE salary > (SELECT AVG(salary) FROM employees WHERE department = d.department); | SQL

SQL - Subqueries

Find the issue in this query:

SELECT name FROM employees e WHERE salary > (SELECT AVG(salary) FROM employees WHERE department = d.department);

AMissing GROUP BY clause in subquery

BAVG function cannot be used in subqueries

CAlias 'd' is undefined in the outer query

DSubquery must return multiple rows

Step-by-Step Solution

Solution:

Step 1: Check alias usage
The subquery references d.department, but alias 'd' is not defined in the outer query.
Step 2: Understand alias scope
Only alias 'e' is defined; using 'd' causes an error.
Final Answer:
Alias 'd' is undefined in the outer query -> Option C
Quick Check:
Alias must be defined before use in correlated subquery [OK]

Quick Trick: Use only defined aliases in correlated subqueries [OK]

Common Mistakes:

MISTAKES

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