SQL Inner JOIN By Two Columns Tricky Example

Here is SQL Inner Join example of two tables. The first thing you need is common key for both tables. That means common fields of both the tables on which you are going to join. If you know table structure of both the tables, it is very easy to find Key field, and you can write join SQL query easily.

SQL Inner JOIN By Two Columns Tricky Example

Tricky SQL Inner Join Example Query

Here you can join Customer_Table and Order_Table using common keys. Here is you can find inner vs outer join differences and which is better.

SELECT
 Customer_Number
 ,a.Customer_Name
 ,b.Order_Number
 ,b.Order_Total
FROM   Customer_Table a
INNER JOIN
        Order_Table b
Using (Customer_Number, phone_number) ;

Bottomline

I used here two tables. One is customer_table and the other one is order_table. Now know the key fields so you can complete your query easily.
Key is: using(customer_number, PHONE_NUMBER)
The columns in the using are common to both the tables.