subsonic 2 join on multiple columns - mysql

Question

I want to transfer the following statement to SubSonic 2.2
SELECT b.*
FROM tableA a
INNER JOIN tableB b
ON (a.year = b.year AND a.month = b.monath AND a.userid = b.userid);
My problem is that SubSonic's SqlQuery.LeftInnerJoin() command has no overload which takes more than one column.
Since any join can be rewritten only using where clauses, I did the following in my sql:
SELECT b.*
FROM tableA a, tableB b
WHERE a.year = b.year
AND a.month = b.month
AND a.userid = b.userid
which should deliver the same result (in fact, at least for mysql, there is logically absolutely no difference between these statements).
But I also got stuck transfering this to subsonic because the "IsEqualTo(...)" member is smart enough to figure out that my parameter is a string and puts it into quotes.
DB.Select("TableB.*")
.From<TableA>()
.From<TableB>()
.Where(TableA.YearColumn).IsEqualTo("TableB.Year")
.And(TableA.MonthColumn).IsEqualTo("TableB.Month")
.And(TableA.UseridColumn).IsEqualTo("TableB.UserId")
(I tried different ways in setting the IsEqualTo parameter)
IsEqualTo(TableB.YearColumn)
IsEqualTo(TableB.YearColumn.QualifiedName)
Either the parameter is interpreted as
TableA.Year = 'TableB.Year'
or I get a SqlQueryException.
Can somebody tell me how to do this query with subsonic (Either the first - with JOIN or the second one)? Thanks

Answer 1

With SubSonic 2 out of the box you can't.
This said, you have the following alternatives:
Extend SubSonic
If you're already familiar with SubSonic, you may consider to add multi-column joins to SubSonic itself.
Use views, Stored procedures, table functions
If you do not want to mess with SubSonics code, use views, stored procedures and/or table functions within sql server. SubSonic makes it easy to access data from views and stored procedures.
Use an InlineQuery
InlineQuery allows you to execute any sql - if it is an option to have bare sql in your code.
Ugly workaround with InlineQuery
If you absolutely want to create your query with SubSonic, you can try this:
SqlQuery q = DB.Select()
.From<TableA>()
.CrossJoin<TableB>()
.Where(TableA.YearColumn).IsEqualTo(0)
.And(TableA.MonthColumn).IsEqualTo(0)
.And(TableA.UseridColumn).IsEqualTo(0);
Build the SQL statement, and replace the parameter names:
string s = q.BuildSqlStatement();
s = s.Replace(q.Constraints[0].ParameterName, TableB.YearColumn.QualifiedName);
s = s.Replace(q.Constraints[1].ParameterName, TableB.MonthColumn.QualifiedName);
s = s.Replace(q.Constraints[2].ParameterName, TableB.UserIdColumn.QualifiedName);
Then use s with an InlineQuery.