public class Stock
    {
        private Model.Consulting.StockId id;
        private int quantity;

        protected Stock () {
            this.id = new StockId();
            this.quantity = -1;
        }

        public Stock(Model.Entities.ComplexArticle article, Model.Entities.Place site, int quantity)
        {
            this.id = new StockId(article, site);
            this.quantity = quantity;
        }

        #region Properties

        public virtual Model.Consulting.StockId Id { get { return id; } set { id = value; } }

        public virtual Model.Entities.ComplexArticle Article { get { return this.id.Article; } set { this.id.Article = value; } }

        public virtual Model.Entities.Place Site { get { return this.id.Site; } set { this.id.Site = value; } }

        public virtual int Quantity { get { return quantity; } set { quantity = value; } }

        public virtual double Value { get { return this.id.Article.Price * this.quantity; } }

        #endregion

    }

    public class StockId
    {
        private Model.Entities.ComplexArticle article;
        private Model.Entities.Place site;

        public StockId()
        {
            this.article = null;
            this.site = null;
        }

        public StockId(Model.Entities.ComplexArticle article, Model.Entities.Place site)
        {
            this.article = article;
            this.site = site;
        }

        #region Properties

        public virtual Model.Entities.ComplexArticle Article { get { return article; } set { article = value; } }

        public virtual Model.Entities.Place Site { get { return site; } set { site = value; } }

        #endregion

        #region ToString, Equals, HashCode

        public override bool Equals(object obj)
        {
            if (this == obj) return true;
            if (obj == null || !obj.GetType().Equals(this.GetType())) return false;

            Model.Consulting.StockId altre = (Model.Consulting.StockId)obj;
            return this.Article == altre.Article && this.Site == altre.Site;
        }

        public override int GetHashCode()
        {
            return this.Site.GetHashCode() + this.Article.GetHashCode() + 74;
        }

        #endregion
    }

SELECT ARTICLE_ID, TO_PLACE_ID SITE, CAST(AMOUNT AS SIGNED INT) QUANTITY FROM STOCK_MOVEMENTS WHERE TO_PLACE_ID IS NOT NULL