How do I use the servicestack ormlite JoinSqlBuilder

Question

There are no samples or docu about this class. If I am wrong I would really be pleased about any link!

I do not understand what I should pass as next parameter and how to make the whole thing execute as query on an SqlConnection.

Someone can help me please?

 var sql = new JoinSqlBuilder<Schoolyear, Period>()
           .Join<Schoolyear, Period>(s => s.Id, p => p.SchoolyearId);
           .Where(p => p.MyDate > DateTime.Now) // This Where clause does not work

 // How to execute the sql?

 // How to attach the query to an SqlConnection?

UPDATE

OK 2 hours later:

using (IDbConnection con = dbFactory.OpenDbConnection())
{
    var sql = new JoinSqlBuilder<Schoolyear, Period>().Join<Schoolyear, Period>(s => s.Id, p => p.SchoolyearId,
       destinationWhere: p => p.LessonDate >= startDateOfWeek && p.LessonDate < endDateOfWeek).ToSql();

    return con.Query(sql); /* There is not Query on the idbconnection although ormlite is using the con.Query in its samples? or return dbConn.Exec(dbCmd => dbCmd.Select<T>()); There is no .Select extension method? */

}

Answer 1

You can find some good examples of JoinBuilder in the unit tests here. To run the join query you need to convert the builder to SQL and then pass it to Select, like this:

var sql = jn.ToSql();
var items = con.Select<SchoolYearPeriod>(sql);

You can also use the join builder in conjunction with the expression visitor, so you can create complex WHERE filters after the join, like this:

SqlExpressionVisitor<SchoolYearPeriod> ev = Db.CreateExpression<SchoolYearPeriod>();
ev.SelectExpression = join.ToSql();
ev.Where(syp => syp.MyDate > DateTime.Now);