topic Re: join in Application Development and Automation Discussions

join

Former Member — Thu, 21 Jun 2007 15:42:39 GMT

what is the difference between left outer join and right outer join?

Re: join

Former Member — Thu, 21 Jun 2007 15:53:39 GMT

AFAIK it works like this...

You got TABLE1 and TABLE2

Using LEFT OUTER JOIN gathers all records from TABLE1 that are not present on TABLE2...And RIGHT OUTER JOIN does the same in reversal order...It gather all records from TABLE2 that are not present on TABLE1....

To me it's just a matter of taste....Because it depends on the order of your tables in the query -;)

Greetings,

Blag.

Re: join

RichHeilman — Thu, 21 Jun 2007 15:53:55 GMT

Don't think that there is such a thing as a RIght Outer Join in Open SQL within ABAP.

http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb39c4358411d1829f0000e829fbfe/frameset.htm

Regards,

RIch Heilman

Re: join

Former Member — Thu, 21 Jun 2007 16:01:30 GMT

INNER JOIN: Retrieves customers with orders only. For example, you want to determine the amount ordered by each customer and you only want to see those who have ordered something

SELECT Customers., Orders.

FROM Customers INNER JOIN Orders ON Customers.CustomerID =

Orders.CustomerID

LEFT OUTER JOIN: Retrieves all customers with or without orders. Order data for customers without orders appears as NULL values. For example, you want to determine the amount ordered by each customer and you need to see who has not ordered anything as well. You can also see the LEFT OUTER JOIN as a mirror image of the RIGHT OUTER JOIN if you switch the side of each table.

SELECT Customers., Orders.

FROM Customers LEFT OUTER JOIN Orders ON Customers.CustomerID =

Orders.CustomerID

RIGHT OUTER JOIN: Retrieves all orders with or without matching customer records. Customer data for orders without customers appears as NULL values. For example, you want to determine if there are any orders in the data with undefined CustomerID values (say, after a conversion or something like it). You can also see the RIGHT OUTER JOIN as a mirror image of the LEFT OUTER JOIN if you switch the side of each table.

SELECT Customers., Orders.

FROM Customers RIGHT OUTER JOIN Orders ON Customers.CustomerID =

Orders.CustomerID