我有一个存储过程,它返回一个动态表作为结果。来自this answer的SQL代码
create table temp
(
date datetime,
category varchar(3),
amount money
)
insert into temp values ('1/1/2012', 'ABC', 1000.00)
insert into temp values ('1/1/2012', 'ABC', 2000.00)
insert into temp values ('2/1/2012', 'DEF', 500.00)
insert into temp values ('2/1/2012', 'DEF', 1500.00)
insert into temp values ('2/1/2012', 'GHI', 800.00)
insert into temp values ('2/10/2012', 'DEF', 700.00)
insert into temp values ('2/10/2012', 'DEF', 800.00)
insert into temp values ('3/1/2012', 'ABC', 1100.00)
CREATE PROCEDURE [dbo].[USP_DYNAMIC_PIVOT]
(
@STATIC_COLUMN VARCHAR(255),
@PIVOT_COLUMN VARCHAR(255),
@VALUE_COLUMN VARCHAR(255),
@TABLE VARCHAR(255),
@AGGREGATE VARCHAR(20) = NULL
)
AS
BEGIN
SET NOCOUNT ON;
DECLARE @AVAIABLE_TO_PIVOT NVARCHAR(MAX),
@SQLSTRING NVARCHAR(MAX),
@PIVOT_SQL_STRING NVARCHAR(MAX),
@TEMPVARCOLUMNS NVARCHAR(MAX),
@TABLESQL NVARCHAR(MAX)
IF ISNULL (@AGGREGATE, '') = ''
BEGIN
SET @AGGREGATE = 'MAX'
END
SET @PIVOT_SQL_STRING ='SELECT top 1 STUFF((SELECT distinct '', '' + CAST(''[''+CONVERT(VARCHAR,'+ @PIVOT_COLUMN+')+'']'' AS VARCHAR(50)) [text()]
FROM '+@TABLE+'
WHERE ISNULL('+@PIVOT_COLUMN+','''') <> ''''
FOR XML PATH(''''), TYPE)
.value(''.'',''NVARCHAR(MAX)''),1,2,'' '') as PIVOT_VALUES
from '+@TABLE+' ma
ORDER BY ' + @PIVOT_COLUMN + ''
DECLARE @TAB AS TABLE(COL NVARCHAR(MAX) )
INSERT INTO @TAB
EXEC SP_EXECUTESQL @PIVOT_SQL_STRING, @AVAIABLE_TO_PIVOT
SET @AVAIABLE_TO_PIVOT = (SELECT * FROM @TAB)
SET @TEMPVARCOLUMNS = (SELECT replace(@AVAIABLE_TO_PIVOT,',',' nvarchar(255) null,') + ' nvarchar(255) null')
SET @SQLSTRING = 'DECLARE @RETURN_TABLE TABLE ('+@STATIC_COLUMN+' NVARCHAR(255) NULL,'+@TEMPVARCOLUMNS+')
INSERT INTO @RETURN_TABLE('+@STATIC_COLUMN+','+@AVAIABLE_TO_PIVOT+')
SELECT *
FROM
(SELECT ' + @STATIC_COLUMN + ' , ' + @PIVOT_COLUMN + ', ' + @VALUE_COLUMN + ' FROM '+@TABLE+' ) a
PIVOT
(
'+@AGGREGATE+'('+@VALUE_COLUMN+')
FOR '+@PIVOT_COLUMN+' IN ('+@AVAIABLE_TO_PIVOT+')
) piv
SELECT * FROM @RETURN_TABLE'
EXEC SP_EXECUTESQL @SQLSTRING
END
这是我在ASP.net Core 2.2中的C#代码
DataTable dt = new DataTable();
using (SqlConnection conn = new SqlConnection(connectionString))
{
SqlCommand sqlComm = new SqlCommand("USP_DYNAMIC_PIVOT", conn);
sqlComm.Parameters.Add(new SqlParameter("@STATIC_COLUMN", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "Date" });
sqlComm.Parameters.Add(new SqlParameter("@PIVOT_COLUMN", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "category" });
sqlComm.Parameters.Add(new SqlParameter("@VALUE_COLUMN", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "amount" });
sqlComm.Parameters.Add(new SqlParameter("@TABLE", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "dbo.temp" });
sqlComm.Parameters.Add(new SqlParameter("@AGGREGATE", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "sum" });
sqlComm.CommandType = CommandType.StoredProcedure;
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = sqlComm;
da.Fill(dt);
}
dt
为空。我已经尝试过跟踪器,并且在那里生成的SQL调用在运行时返回正确的结果。跟踪器还显示该过程已完成该过程。有什么我想念的吗?
编辑:我已经在这里的一些答案中添加了Nuget包System.Data.Common
和System.Data.SqlClient
,但没有任何变化。
编辑2:我正在修改我的代码以获得完整的工作示例。这取自this example,但问题仍然存在。跟踪器中的过程执行是
exec USP_DYNAMIC_PIVOT @STATIC_COLUMN='Date',@PIVOT_COLUMN='category',@VALUE_COLUMN='amount',@TABLE='dbo.temp',@AGGREGATE='sum'
这是正确的电话。
我(仍然)无法重复这一点。正如您在跟踪活动时所看到的,ADO.NET在执行命令之前不会尝试确定结果集元数据。相反,它会检查SqlDataReader中返回的元数据以创建DataTable模式:
using System;
using System.Data;
using System.Data.SqlClient;
namespace ConsoleApp15
{
class Program
{
static void Main(string[] args)
{
var connectionString = "Server=.;Database=tempdb;integrated security=true";
DataTable dt = new DataTable();
using (SqlConnection conn = new SqlConnection(connectionString))
{
SqlCommand sqlComm = new SqlCommand("USP_DYNAMIC_PIVOT", conn);
sqlComm.Parameters.Add(new SqlParameter("@STATIC_COLUMN", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "Date" });
sqlComm.Parameters.Add(new SqlParameter("@PIVOT_COLUMN", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "category" });
sqlComm.Parameters.Add(new SqlParameter("@VALUE_COLUMN", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "amount" });
sqlComm.Parameters.Add(new SqlParameter("@TABLE", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "dbo.temp" });
sqlComm.Parameters.Add(new SqlParameter("@AGGREGATE", SqlDbType.VarChar) { Direction = ParameterDirection.Input, Value = "sum" });
sqlComm.CommandType = CommandType.StoredProcedure;
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = sqlComm;
da.Fill(dt);
Console.WriteLine($"SqlClient: { typeof(SqlConnection).Assembly.FullName}");
dt.TableName = "sp_test";
dt.WriteXmlSchema(Console.Out);
Console.WriteLine();
Console.WriteLine($"rows {dt.Rows.Count}");
}
}
}
}
输出
SqlClient: System.Data.SqlClient, Version=4.5.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
<?xml version="1.0" encoding="ibm437"?>
<xs:schema id="NewDataSet" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<xs:element name="NewDataSet" msdata:IsDataSet="true" msdata:MainDataTable="sp_test" msdata:UseCurrentLocale="true">
<xs:complexType>
<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:element name="sp_test">
<xs:complexType>
<xs:sequence>
<xs:element name="Date" type="xs:string" minOccurs="0" />
<xs:element name="ABC" type="xs:string" minOccurs="0" />
<xs:element name="DEF" type="xs:string" minOccurs="0" />
<xs:element name="GHI" type="xs:string" minOccurs="0" />
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:choice>
</xs:complexType>
</xs:element>
</xs:schema>
rows 4