[Solved] Identify the error in this query:SELECT id, name FROM Employees UNION SELECT id FROM Managers; — Ans: Different number of columns in SELECT statements | SQL

SQL - Set Operations

Identify the error in this query:
SELECT id, name FROM Employees UNION SELECT id FROM Managers;

AUsing UNION without ORDER BY

BMissing WHERE clause in second SELECT

CUNION cannot be used with different tables

DDifferent number of columns in SELECT statements

Step-by-Step Solution

Solution:

Step 1: Check column counts in SELECTs
First SELECT has 2 columns, second SELECT has 1 column.
Step 2: Understand UNION column requirement
UNION requires same number of columns in both SELECT queries.
Final Answer:
Different number of columns in SELECT statements -> Option D
Quick Check:
Column count mismatch error = A [OK]

Quick Trick: UNION needs same number of columns in both SELECTs [OK]

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