Invercargill-Sql/examples/projections/sales-report.vala

using Invercargill.Expressions;
using InvercargillSql.Orm;
using InvercargillSql.Orm.Projections;

/**
 * Aggregate projection demonstrating GROUP BY and aggregate functions.
 */
public class SalesReport : Object {
    public string category { get; set; }
    public int64 total_orders { get; set; }
    public double total_revenue { get; set; }
    public double avg_order_value { get; set; }
    
    public SalesReport() {
        category = "";
    }
    
    public static void configure_projection(ProjectionBuilder<SalesReport> p) throws ProjectionError {
        p.source<Order>("o")
            .join<Product>("p", expr("o.product_id == p.id"))
            .group_by(expr("p.category"))
            .select<string>("category", expr("p.category"), (x, v) => x.category = v)
            .select<int64?>("total_orders", expr("COUNT(o.id)"), (x, v) => x.total_orders = v)
            .select<double?>("total_revenue", expr("SUM(o.total)"), (x, v) => x.total_revenue = v)
            .select<double?>("avg_order_value", expr("AVG(o.total)"), (x, v) => x.avg_order_value = v);
    }
}