我正在尝试更新Microsoft报告.它的作用是写出从转换过程中排除的客户数量以及原因.目前,程序将所有已删除的客户端写回服务器,然后将其查询回来以填充带有结果的专业表.
这是当前的查询：
SELECT DeletedClients.Reason,COUNT(DeletedClients.Reason) AS Number,CAST(CAST(COUNT(DeletedClients.Reason) AS float)
/ CAST(t.Total AS float)
* 100 AS numeric(4,1)) AS percentage
FROM DeletedClients CROSS JOIN
(SELECT COUNT(*) AS Total
FROM DeletedClients AS DeletedClients_1
WHERE (ClinicID = @ClinicID)) AS t
WHERE (DeletedClients.ClinicID = @ClinicID)
AND (DeletedClients.TotalsIdent = @ident)
GROUP BY DeletedClients.Reason,t.Total
ORDER BY Number DESC
我想做的是不将DeletedClients写入服务器,因为它已作为DataTable存在于我的程序的内存中,它只会减慢报告速度并使用我们不需要保存的信息填充数据库.
我的主要问题是：要么：
如何查询数据表以创建一个新的内存数据表,其结果与我写出sql服务器并使用上面的查询读回来的结果相同？
要么
如何在Microsoft Reports中为Tablix中的项目执行group by子句= Fields！Reason.Value = Fields！Number.Value = Fields！percentage.Value类似于上面查询的返回结果？
解决方法
您可以使用DataTable.Select查询DataTable.
DataTable table = GetDataTableResults();
DataTable results = table.Select("SomeIntColumn > 0").CopyToDataTable();
或者对于更复杂的查询,您可以使用LINQ查询DataTable：
DataTable dt = GetDataTableResults();
var results = from row in dt.AsEnumerable()
group row by new { SomeIDColumn = row.Field<int>("SomeIDColumn") } into rowgroup
select new
{
SomeID = rowgroup.Key.SomeIDColumn,SomeTotal = rowgroup.Sum(r => r.Field<decimal>("SomeDecimalColumn"))
};
DataTable queryResults = new DataTable();
foreach (var result in query)
queryResults.Rows.Add(new object[] { result.SomeID,result.SomeTotal });
