Database Joins

ryanburnett · September 17th, 2010, 01:27 PM

Hi,

I'm now upto databases in my re-read of the book, Chapter12. It talks about table joins in database queries, such as:

Code:

LEFT OUTER JOIN

Code:

INNER JOIN

I understand that it allows you to take data from two tables and collums, then sorta stick the data togethor and display it as a whole. But what is the difference? The LEFT OUTER and INNER joins both output the same? So why change the relationships between the tables

Also Imar, just a trivial question, when you are working on sites do you add all of your GridView controls (for example) in design view or strictly keep in code view? Just a question as I see how easy it is to do things in design view! I have been trying to stay in code view so I can learn the inner workings of things

Anyways, thanks a lot

and I hope I'm just a little off the ball! / Ryan

Imar · September 17th, 2010, 03:21 PM

Quote:

The LEFT OUTER and INNER joins both output the same

Nope. An INNER JOIN returns records that match on both sides; a LEFT JOIN returns all records on the left side, whether they have matching records or not and includes the matching records on the right side.

You may find this Wiki page useful: http://en.wikipedia.org/wiki/Join_(SQL)

I spend time both in design view and in code view. Setting up handlers for example is way easier in Design View as it requires lots of manual coding in code view.

Cheers,

Imar