Question

我想在NHibernate写一个预测问题,即小组按日期记录这些记录的“Tax”外地价值。我的问题是,数据库具有时间价值,我会如何按日期而不是时间记录。下面是我的法典

template.Criteria.SetProjection(
                Projections.ProjectionList()
                .Add(Projections.GroupProperty("IssueDatetime"), "DateVal")
                .Add(Projections.Sum("Tax"), "TotalFare")
            );

该数据库将发行时间领域作为时间类别储存。我现在要逐日计算税额,忽略时间。任何人能否帮助我满足上述要求?

Answer 1

第一次预测使用如下:

Projections.GroupProperty(
    Projections.SqlFunction("date",
                            NHibernateUtil.Date,
                            Projections.GroupProperty("IssueDateTime")))

NH 2.x:

Projections.GroupProperty(
    Projections.SqlFunction(new SQLFunctionTemplate(
                                NHibernateUtil.Date,
                                "dateadd(dd, 0, datediff(dd, 0, ?1))"),
                            NHibernateUtil.Date,
                            Projections.GroupProperty("IssueDateTime")))

Answer 2

Assuming SQL Server and T-SQL, this ICriteria will do it.

IList results = Session.CreateCriteria(typeof(Record), "record")
    .SetProjection(Projections.ProjectionList()
        .Add(Projections.SqlGroupProjection("CONVERT(date, {alias}.[IssueDatetime]) AS [DateVal]", "CONVERT(date, {alias}.[IssueDatetime])", new[] { "DateVal" }, new IType[] { NHibernateUtil.Date }))
        .Add(Projections.Sum("Tax"), "TotalFare"))
    .List();

The following is produced.

SELECT CONVERT(date, this_.[IssueDatetime]) AS [DateVal], sum(this_.Tax) as y1_ FROM IgnoreTime_Record this_ GROUP BY CONVERT(date, this_.[IssueDatetime])

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