I can't understand GroupJoin where i will need it in database relationships.

Posted by Freshblood on Stack Overflow See other posts from Stack Overflow or by Freshblood
Published on 2010-06-12T22:05:47Z Indexed on 2010/06/12 22:13 UTC
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c#

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.NET

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LINQ

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query

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join

Hello Everybody

I am thinking 5-6 hours to understand something about GroupJoin. I am talking about query with linq for Database tables.I understand what Join and GroupJoin does but I really couldn't understand where i will need it.I feel that Join does all what i will need but if there is something which Join can't without GroupJoin so i feel that situation is meaningless or useless.

For example:

Persons table in relation with Phones and Phones table hold foreign keys of Persons and one person can have one more phone number.If we want to brings all persons who has phone numbers and who hasn't too so we will need GroupJOin but what for we will need this query ?

Can u give me good reason , example or explenation for using GroupJoin ?

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