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);