How to find duplicates in SQL from one table while joining up to another?

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So I have two tables, let’s call them Orders and Customers. In the orders table there are duplicate records which I need to identify. I am attempting to select event_key and order_item while doing an inner join on the event_key, and also selecting the order_key and customer_key from the other table that has the event_key in common.

Orders table

  • Event_key
  • Order_item

Customers table

  • Event_key
  • Order_key
  • Customer_key

By doing this, I’m seeing more duplicate entries than there actually are. To put it simply, I just want to find the duplicates on the orders table, and select the associating order and customer keys from the customers table.

Select count(*) as count from orders_tbl o 
Inner join customers_tbl c 
on o.event_key = c.event_key
group by o.event_key, o.order_item, c.order_key, c.customer_key
where o.event_key = 1 and o.order_item = 16 and c.order_key = 2 and c.customer_key = 6

How do I go about this?

0 Answers
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