Which of the following is the correct syntax to combine two SELECT queries using UNION in PostgreSQL?

easy📝 Syntax Q12 of 15

PostgreSQL - Set Operations and Advanced Queries

ASELECT col1 FROM table1 JOIN SELECT col1 FROM table2;

BSELECT col1 FROM table1 UNION SELECT col1 FROM table2;

CSELECT col1 FROM table1 + SELECT col1 FROM table2;

DSELECT col1 FROM table1 INTERSECT SELECT col1 FROM table2;

Step-by-Step Solution

Solution:

Step 1: Recall UNION syntax
The correct syntax uses UNION keyword between two SELECT statements with matching columns.
Step 2: Check options
Only SELECT col1 FROM table1 UNION SELECT col1 FROM table2; is correct. JOIN is for table joins; + is invalid syntax; INTERSECT is a different operation.
Final Answer:
SELECT col1 FROM table1 UNION SELECT col1 FROM table2; -> Option B
Quick Check:
UNION syntax = SELECT ... UNION SELECT ... [OK]

Quick Trick: UNION joins SELECTs with UNION keyword, no + or JOIN [OK]

Common Mistakes:

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