In the samples SearchBuilderController.cs adding addition joins show up in that search builder query:
.Field(new Field("users.site")
.Options(new Options()
.Table("sites")
.Value("id")
.Label("name")
)
)
.Field(new Field("sites.name")
.SearchBuilderOptions(new SearchBuilderOptions()
.Label("sites.name")
.Value("sites.name")
.LeftJoin("sites", "sites.id", "=", "users.site")
)
)
.LeftJoin("sites", "sites.id", "=", "users.site")
.LeftJoin("user_dept", "users.id", "=", "user_dept.user_id")
SELECT sites.name as 'value', sites.name as 'label'
FROM users
LEFT JOIN sites ON sites.id = users.site
LEFT JOIN user_dept ON users.id = user_dept.user_id
GROUP BY sites.name