Скачать или смотреть 🔥 How to Remove Duplicate Rows in SQL Using CTID | SQL Deduplication Tutorial

📌 Struggling with duplicate records in PostgreSQL? Learn how to identify and remove duplicates while keeping only one unique occurrence of each (customer_id, order_id) pair using CTID.

🔹 What You’ll Learn in This Video:
✅ How to find duplicate records in PostgreSQL
✅ How to use CTID for efficient row deletion
✅ How to keep only one unique occurrence of each record
✅ Best practices for handling duplicates

📌 Data Set Creation (SQL Code):

CREATE TABLE orders (
customer_id INT,
order_id INT
);

INSERT INTO orders (customer_id, order_id) VALUES
(101, 2001),
(102, 2002),
(103, 2003),
(104, 2004),
(105, 2005),
(106, 2006),
(107, 2007),
(108, 2008),
(109, 2009),
(110, 2010),
-- Duplicates
(101, 2001), -- Duplicate 2 times
(103, 2003), -- Duplicate 2 times
(103, 2003),
(105, 2005), -- Duplicate 3 times
(105, 2005),
(106, 2006), -- Duplicate 3 times
(106, 2006),
(107, 2007), -- Duplicate 4 times
(107, 2007),
(107, 2007)

💻 SQL Query Used in This Video:

delete from orders
where ctid in (

select ctid
from (
select customer_id, order_id,
row_number()over(partition by customer_id, order_id ) as rn,
ctid
from orders
)
where rn 〉1
)

#PostgreSQL #SQL #DataCleaning #CTID #SQLTutorial #analytics #python 🚀