Solution:Step 1: Understand UNION removes duplicatesThe query combines rows from both tables but removes duplicate rows like (2, 'Bob').Step 2: List unique rows from both tablesTable1 has (1, 'Alice'), (2, 'Bob'); Table2 has (2, 'Bob'), (3, 'Charlie'). After UNION, duplicates removed, result is (1,

[Solved] Given two tables:Table1:id | name1 | 'Alice'2 | 'Bob'Table2:id | name2 | 'Bob'3 | 'Charlie'What is the result of this query?SELECT id, name FROM Table1 UNION SELECT id, name FROM Table2; | PostgreSQL

PostgreSQL - Set Operations and Advanced Queries

ARows: (1, 'Alice'), (2, 'Bob'), (2, 'Bob'), (3, 'Charlie')

BRows: (1, 'Alice'), (2, 'Bob'), (3, 'Charlie')

CRows: (2, 'Bob'), (3, 'Charlie')

DRows: (1, 'Alice'), (3, 'Charlie')

Step-by-Step Solution

Solution:

Step 1: Understand UNION removes duplicates
The query combines rows from both tables but removes duplicate rows like (2, 'Bob').
Step 2: List unique rows from both tables
Table1 has (1, 'Alice'), (2, 'Bob'); Table2 has (2, 'Bob'), (3, 'Charlie'). After UNION, duplicates removed, result is (1, 'Alice'), (2, 'Bob'), (3, 'Charlie').
Final Answer:
Rows: (1, 'Alice'), (2, 'Bob'), (3, 'Charlie') -> Option B
Quick Check:
UNION removes duplicates = Rows: (1, 'Alice'), (2, 'Bob'), (3, 'Charlie') [OK]

Quick Trick: UNION removes duplicates from combined results [OK]

Common Mistakes:

Expecting duplicates to appear
Confusing UNION with UNION ALL
Ignoring duplicate rows

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Given two tables:

Step 1: Understand UNION removes duplicates

Step 2: List unique rows from both tables

Final Answer:

Quick Check:

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