任何人都知道如何使用 Projections.Conditional 来产生类似“case ... when ...”的东西
以下代码给出了错误的查询：
IProjection isError = Projections.Conditional( Expression.Eq( "event.LogLevel", eLogLevel.Fatal.ToString( ) ), Projections.Constant( 1 ), Projections.Constant( 0 ) );
ICriteria criteria = Session.CreateCriteria( typeof( LogEvent ), "event" )
.Add( Restrictions.Eq( "event.ApplID", "LogEventViewer" ) )
.SetProjection( Projections.ProjectionList( )
.Add( Projections.GroupProperty( "event.ApplID" ) )
.Add( Projections.RowCount( ), "TotalCount" )
.Add( Projections.Sum( isError ), "ErrorCount" )
);
生成的语句不完整，参数顺序错误。
exec sp_executesql N'
SELECT this_.strApplID as y0_
, count(distinct this_.lngLogEventID) as y1_
, sum((case when this_.strLogLevel = ? then ? else ? end)) as y2_
, this_.strApplID as y3_
FROM qryLogEvent this_
WHERE this_.strApplID = @p0
GROUP BY this_.strApplID'
,N'@p0 nvarchar(5),@p1 int,@p2 int,@p3 nvarchar(14)'
,@p0=N'Fatal',@p1=1,@p2=0,@p3=N'LogEventViewer'
使用 Projections.Conditional 的正确方法是什么？