wp-how-to-use-petapoco-with-umbraco-10.cs

var sql = new Sql()
    .Select("*")
    .From<Movie>(dbContext.SqlSyntax)
    .Where<Movie>(m => m.Title == "Avatar", dbContext.SqlSyntax);

var avatar = dbContext.Database.Fetch<Movie>(sql).FirstOrDefault();

sql = new Sql()
    .Select("Actors.*")
    .From<Actor>(dbContext.SqlSyntax)
    .InnerJoin<ActorMovie>(dbContext.SqlSyntax)
    .On<ActorMovie, Actor>(dbContext.SqlSyntax, am => am.ActorId, ac => ac.Id)
    .Where<ActorMovie>(am => am.MovieId == a.Id, dbContext.SqlSyntax);

avatar.Actors = dbContext.Database.Fetch<Actor>(sql);