[Solved] Find the issue in this query:SELECT employee_id, (SELECT MAX(salary) FROM employees WHERE department_id = department_id) AS max_salary FROM employees; | SQL

SQL - Subqueries

Find the issue in this query:

SELECT employee_id, (SELECT MAX(salary) FROM employees WHERE department_id = department_id) AS max_salary FROM employees;

AThe subquery's WHERE clause compares the same column, causing incorrect results

BMissing alias for subquery column

CSubquery returns multiple rows error

DNo issue, query runs correctly

Step-by-Step Solution

Solution:

Step 1: Examine WHERE clause in subquery
Condition compares department_id to itself, always true, not correlated to outer query.
Step 2: Effect on results
Subquery returns max salary for all employees, not per department of outer row.
Final Answer:
The subquery's WHERE clause compares the same column, causing incorrect results -> Option A
Quick Check:
Incorrect correlation in subquery WHERE clause [OK]

Quick Trick: Correlate subquery columns properly to outer query [OK]

Common Mistakes:

MISTAKES

Master "Subqueries" in SQL

9 interactive learning modes - each teaches the same concept differently

More SQL Quizzes

Find the issue in this query: