Right and left join in LINQ

Suppose we have a table like following structure

User | age| Data |Growth
------------------------                           
1    |2   |43.5  |46.5                           
1    |2   |43.5  |49.5     
1    |2   |43.5  |48.5     
2    |3   |44.5  |                          
3    |4   |45.6  |

Assuming that you still require a left join; here's how you do a left join in Linq:

var results = from data in userData
              join growth in userGrowth
              on data.User equals growth.User into joined
              from j in joined.DefaultIfEmpty()
              select new 
              {
                  UserData = data,
                  UserGrowth = j
              };

If you want to do a right join, just swap the tables that you're selecting from over, like so:

var results = from growth in userGrowth
              join data in userData
              on growth.User equals data.User into joined
              from j in joined.DefaultIfEmpty()
              select new 
              {
                  UserData = j,
                  UserGrowth = growth
              };

The important part of the code is the into statement, followed by the DefaultIfEmpty. This tells Linq that we want to have the default value (i.e. null) if there isn't a matching result in the other table.