How do I write the equivalent of a SQL LEFT JOIN in LINQ?

Question

I need to convert this SQL to LINQ, and would really appreciate some help.

SELECT * FROM Adx_eventSet AS es
LEFT JOIN afx_eventsponsor_eventSet AS spon
ON es.Adx_eventId = spon.adx_eventid

Ive tried this but it's not a left join and so only pulled in the one result.

from t in Adx_eventSet
join x in adx_eventsponsor_eventSet on t.Adx_eventId equals x.adx_eventid
select t

heey I asked more or less the same question today (http://stackoverflow.com/questions/16099057/translate-from-sql-to-linq) I hope you can find some us full informations — Mingebag, Apr 19 '13 at 14:30
Another example... http://stackoverflow.com/questions/2742814/left-outer-join-problem — msmucker0527, Apr 19 '13 at 14:31

Sam Leach · Accepted Answer · 2013-04-19T15:00:10.210

You want to use DefaultIfEmpty(). See below.

var leftJoin = from adx_event in Adx_eventSet
               join adx_eventsponsor in adx_eventsponsor_eventSet
               on adx_event.Adx_eventId equals adx_eventsponsor.adx_eventid into j 
               from adx_eventsponsor in j.DefaultIfEmpty()
               select new 
               { 
                   Name = adx_event.Name,
                   Name = adx_eventsponsor != null ? adx_eventsponsor.Name : null  
               };

Assuming each table has a Name property.

How do I write the equivalent of a SQL LEFT JOIN in LINQ?

1 Answers1