Join Properties - Please Explain

[Howard]

Hi,

I dont understand what the following meant. Would someone please explain to me in plain english with examples? I have searched online but still confused.

1. Only include rows where the joined fields from both tables are equal.


2. Include ALL records from 'Customers' and only those records from 'Orders' where the joined fields are equal.
3. Include ALL records from 'Orders' and only those records from 'Customers' where the joined fields are equal.

Thanks

[ItsMe]

Item #2 will create a LEFT join where you get a one to many.

Considering the names of the tables, I would choose this if you are trying to query Orders associated to each Customer. This way you will see all customers in the customers table and all of the associated records, whether or not a customer has an order. Particulary helpful when you add criteria to your query like a date range, or delivery status of orders.

Item #1 will only show records where there is a match. So, If you had a form bound to this query, you will not see a customer that did not place an order. Even if said customer has a record in the customer table.

[June7]

Review http://www.w3schools.com/sql/sql_join.asp