[Solved] Given the tables and query below, what will be the output?Table X:id | value1 | 'A'2 | 'B'Table Y:code | val2 | 'B'3 | 'C'Query:SELECT id, value FROM XUNIONSELECT code, val FROM Y; | SQL

SQL - Set Operations

Given the tables and query below, what will be the output?

Table X:
id | value
1  | 'A'
2  | 'B'

Table Y:
code | val
2    | 'B'
3    | 'C'

Query:
SELECT id, value FROM X
UNION
SELECT code, val FROM Y;

ASyntax error due to column name mismatch

B[ (1, 'A'), (2, 'B'), (3, 'C') ]

C[ (1, 'A'), (3, 'C') ]

D[ (1, 'A'), (2, 'B'), (2, 'B'), (3, 'C') ]

Step-by-Step Solution

Solution:

Step 1: Check column counts and types
Both queries select 2 columns with compatible types (INT and VARCHAR). Column names differ but that is allowed.
Step 2: Understand UNION behavior
UNION removes duplicates. Rows (2, 'B') appear in both tables, so only one copy appears in result.
Final Answer:
[ (1, 'A'), (2, 'B'), (3, 'C') ] -> Option B
Quick Check:
UNION removes duplicates = D [OK]

Quick Trick: UNION removes duplicates, column names don't matter [OK]

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