How does a recursive CTE help in retrieving all levels of subordinates for a manager in an employee hierarchy table employees(id, name, manager_id)?

hard📝 Application Q9 of 15

SQL - Common Table Expressions (CTEs)

How does a recursive CTE help in retrieving all levels of subordinates for a manager in an employee hierarchy table employees(id, name, manager_id)?

ABy repeatedly joining the CTE to itself to traverse the hierarchy until no more subordinates are found

BBy using a simple GROUP BY to aggregate all subordinates under a manager

CBy creating temporary tables for each level of subordinates manually

DBy filtering employees with a WHERE clause on manager_id only once

Step-by-Step Solution

Solution:

Step 1: Understand recursive CTEs
Recursive CTEs allow a query to refer to its own output to perform iterative processing.
Step 2: Apply to employee hierarchy
The recursive CTE starts with direct subordinates and repeatedly joins to find indirect subordinates.
Final Answer:
By repeatedly joining the CTE to itself to traverse the hierarchy until no more subordinates are found -> Option A
Quick Check:
Recursive self-join is key for hierarchical queries [OK]

Quick Trick: Recursive CTEs traverse hierarchies iteratively [OK]

Common Mistakes:

Using GROUP BY instead of recursion
Manually creating multiple temporary tables
Filtering only direct subordinates

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More SQL Quizzes

How does a recursive CTE help in retrieving all levels of subordinates for a manager in an employee hierarchy table employees(id, name, manager_id)?

Step 1: Understand recursive CTEs

Step 2: Apply to employee hierarchy

Final Answer:

Quick Check:

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