Beginner LevelPostgreSQL
What is the RETURNING clause and how does it retrieve generated columns?
❓ Interview Prompt: Explain RETURNING clause on INSERT, UPDATE, and DELETE statements, eliminating secondary SELECT queries, and RETURNING into CTEs.
The 'RETURNING' clause allows data modification statements ('INSERT', 'UPDATE', 'DELETE') to return modified row values immediately:
Primary Benefit:
Eliminates the need for secondary 'SELECT' queries to fetch auto-generated primary key IDs, default values, or 'updated_at' timestamps!
Code Implementation Example
sql
INSERT INTO customers (name, email)
VALUES ('Alice Smith', 'alice@example.com')
RETURNING id, created_at;💡Retrieving auto-generated primary key ID using RETURNING clause.
🎯 Interview Key Takeaway
Use the RETURNING clause to immediately obtain generated primary keys and default values from write operations.
#RETURNING#INSERT#UPDATE#Beginner
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