[Solved] Identify the error in this query:SELECT department, role, COUNT(*) FROM employees GROUP BY department; | SQL

SQL - GROUP BY and HAVING

Identify the error in this query:

SELECT department, role, COUNT(*) FROM employees GROUP BY department;

AMissing role column in GROUP BY clause

BCOUNT(*) cannot be used with GROUP BY

Cdepartment should not be in GROUP BY

DSELECT must include only aggregated columns

Step-by-Step Solution

Solution:

Step 1: Check SELECT columns vs GROUP BY columns
Columns in SELECT that are not aggregated must appear in GROUP BY. Here, role is in SELECT but missing in GROUP BY.
Step 2: Understand aggregation rules
COUNT(*) is valid, but all non-aggregated columns must be grouped to avoid errors.
Final Answer:
Missing role column in GROUP BY clause -> Option A
Quick Check:
All non-aggregated SELECT columns must be in GROUP BY [OK]

Quick Trick: Include all non-aggregated SELECT columns in GROUP BY [OK]

Common Mistakes:

MISTAKES

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