Merge data in tables

You can conditionally insert, update, or delete existing data in Hive tables using the ACID MERGE statement.

1. Construct a query to update the customers' names and states in customer table to match the names and states of customers having the same IDs in the new_customer_stage table.
2. Enhance the query to insert data from new_customer_stage table into the customer table if none already exists.

   MERGE INTO customer USING (SELECT * FROM new_customer_stage) sub ON sub.id = customer.id 
   WHEN MATCHED THEN UPDATE SET name = sub.name, state = sub.new_state 
   WHEN NOT MATCHED THEN INSERT VALUES (sub.id, sub.name, sub.state);