Complex SQL 2 | find new and repeat customers | SQL Interview Questions

This video is about finding new and repeat customers .using SQL. In this video we will learn following concepts: how to approach complex query step by step how to use CASE WHEN with SUM how to use common table expression (CTE) Here is the script : create table customer_orders ( order_id integer, customer_id integer, order_date date, order_amount integer ); select * from customer_orders insert into customer_orders values(1,100,cast('2022-01-01' as date),2000),(2,200,cast('2022-01-01' as date),2500),(3,300,cast('2022-01-01' as date),2100) ,(4,100,cast('2022-01-02' as date),2000),(5,400,cast('2022-01-02' as date),2200),(6,500,cast('2022-01-02' as date),2700) ,(7,100,cast('2022-01-03' as date),3000),(8,400,cast('2022-01-03' as date),1000),(9,600,cast('2022-01-03' as date),3000) ;