Add support for counts in ListView columns

[YodasMyDad]

listviews, could you potentially do things like counts for column values? i.e. Count children and display that?

[mattbrailsford]

I need to think of a nicer API, but I've implemented a SqlQueryBuildingNotification and SqlQueryBuiltNotification that let you intercept the SQL query being generated by the default repository so you could use these to add a sub query into the default SELECT * FROM statement and then have some result columns on your poco model.

public class MyQueryBuildingNotification : INotificationHandler<SqlQueryBuildingNotification>
{
    public void Handle(SqlQueryBuildingNotification notification)
    {
        notification.Args.Sql = Sql.Builder
            .Append("SELECT * FROM (")
                .Append("SELECT c.*, c2.NumberOfReplies")
                .Append("FROM Comment c")
                .Append("INNER JOIN (")
                    .Append("SELECT c3.InReplyToId, COUNT(c3.InReplyToId) as NumberOfReplies")
                    .Append("FROM Comment c3")
                    .Append("GROUP BY c3.InReplyToId")
                .Append(") as c2 ON c2.InReplyToId = c1.Id")
            .Append(") as Comment");
    }
}

--

public class Comment
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public string Body { get; set; }

    [ResultColumn]
    public int NumberOfReplies { get; set; }
}

The only other alternative right now is to implement your own Repository https://docs.getkonstrukt.net/api/repositories

[mattbrailsford]

Just thought, the "right" way to do this would be to potentially have a custom SQL view and query that view rather than directly query the table. Maybe we can add something to the ListView config to provide a view name to query rather than the normal table name. 🤔