nhibernate - 基準APIを使用してnhibernateの範囲でグループ化する方法

Question

CriteriaAPIで記述したいSQLがあります。

SELECT CASE 
WHEN total_pages = 0 THEN '0 pages'
WHEN total_pages BETWEEN 1 AND 3 THEN '1-3 pages'
WHEN total_pages BETWEEN 4 AND 6 THEN '4-6 pages'
WHEN total_pages > 6 THEN '7 + pages'
END AS pagerange, sum(total_pages) AS 'Total'
FROM dbo.connector_log_entry
GROUP BY 
CASE 
WHEN total_pages = 0 THEN '0 pages'
WHEN total_pages BETWEEN 1 AND 3 THEN '1-3 pages'
WHEN total_pages BETWEEN 4 AND 6 THEN '4-6 pages'
WHEN total_pages > 6 THEN '7 + pages'
END
ORDER BY pagerange

Answer 1

var groupBy = @"
    CASE
      WHEN total_pages = 0 THEN '0 pages'
      WHEN total_pages BETWEEN 1 AND 3 THEN '1-3 pages'
      WHEN total_pages BETWEEN 4 AND 6 THEN '4-6 pages'
      WHEN total_pages > 6 THEN '7 + pages'
    END";
var pagerange = Projections.SqlGroupProjection(groupBy + " pagerange",
                                               groupBy,
                                               new[] { "pagerange" },
                                               new[] { NHibernateUtil.String });
var results = session.CreateCriteria<ConnectorLogEntry>()
                     .SetProjection(pagerange,
                                    Projections.Sum("TotalPages"))
                     .List();

これは、クラスが呼び出さConnectorLogEntryれ、total_pages列にマップされたプロパティが呼び出されることを前提としていますTotalPages。

ORDER BYビットのおかげですが、いつでもクライアント側で並べ替えることができます。