如何使用criteria api在nhibernate中按范围分组

Question

我有想要在Criteria api中编写的sql：

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();

这里假设您的类名为ConnectorLogEntry，映射到total_pages列的属性名为TotalPages。

我欠你一个比特的订单，但你总是可以在客户端排序。