SQL - INNER JOIN
What is the primary advantage of using a self join on a table containing hierarchical data?
What is the primary advantage of using a self join on a table containing hierarchical data?
easy📝 Conceptual Q1 of 15
Step-by-Step Solution
Solution:
Step 1: Understand self join
A self join is used to join a table to itself to compare rows within the same table.Step 2: Apply to hierarchical data
Hierarchical data often has parent-child relationships within the same table, which self join helps to relate.Final Answer:
To compare rows within the same table based on a related column -> Option DQuick Check:
Self join compares rows in one table [OK]
Quick Trick: Self join compares rows within the same table [OK]
Common Mistakes:
MISTAKES- Confusing self join with joining two different tables
- Thinking self join creates new tables
- Assuming self join aggregates data
Master "INNER JOIN" in SQL
Want More Practice?
15+ quiz questions · All difficulty levels · Free
Free Signup - Practice All QuestionsMore SQL Quizzes