我正在从我的 C# ASP.Net 应用程序中调用一个 SQL 函数 (UDF)。我正在调用的函数需要一个“唯一标识符”类型的参数。
如果我拨打电话并在 SqlCommand 的 CommandText 中传递“null”,结果会在大约 3 秒后返回......
SqlCommand Command = new SqlCommand();
Command.Connection = (SqlConnection)(DbDataModifier.CreateConnection());
Command.CommandText = "select * from GetLocalFirmLoginsSummary(null) order by Date asc"
Command.CommandType = CommandType.Text;
Command.Connection.Open();
SqlDataReader Reader = Command.ExecuteReader(); // takes 3 seconds
但是,如果我进行调用并将 DBNull.Value 作为 SqlParameter 传递,结果需要 60 多秒才能返回......
SqlCommand Command = new SqlCommand();
Command.Connection = (SqlConnection)(DbDataModifier.CreateConnection());
Command.CommandText = "select * from GetLocalFirmLoginsSummary(@CustomerGroupID) order by Date asc"
Command.CommandType = CommandType.Text;
SqlParameter Param = new SqlParameter();
Param.ParameterName = "@CustomerGroupID";
Param.SqlDbType = SqlDbType.UniqueIdentifier;
Param.Direction = ParameterDirection.Input;
Param.IsNullable = true;
Param.Value = DBNull.Value;
Command.Parameters.Add(Param);
Command.Connection.Open();
SqlDataReader Reader = Command.ExecuteReader(); // takes over 60 seconds
如果我在 SQL Management Studio 中运行相同的查询,即使将 null 作为参数传递也需要大约 3 秒...
declare @CustomerGroupID uniqueidentifier
set @CustomerGroupID = null
select * from GetLocalFirmLoginsSummary(@CustomerGroupID)
我调用的函数定义为:
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER FUNCTION [dbo].[GetLocalFirmLoginsSummary]
(
@CustomerGroupID uniqueidentifier
)
RETURNS TABLE
AS
RETURN
(
SELECT CustomerGroupID, CustomerGroupName, USR, DATEADD(MONTH, DATEDIFF(MONTH, 0, createdDate), 0) AS Date, COUNT(*) AS Quantity
FROM dbo.GetLocalFirmLogins(@CustomerGroupID) AS Logins
GROUP BY USR, CustomerGroupID, CustomerGroupName, DATEADD(MONTH, DATEDIFF(MONTH, 0, createdDate), 0)
)
...
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER FUNCTION [dbo].[GetLocalFirmLogins]
(
@CustomerGroupID uniqueidentifier
)
RETURNS TABLE
AS
RETURN
(
SELECT vw_CustomerGroupAccountDetails.CustomerGroupID, vw_CustomerGroupAccountDetails.CustomerGroupName, Organisations.USR, Organisations.town AS FirmTown,
Users.id AS ID, Users.userName, Users.password, Users.isPartner, Users.isFeeEarner, Users.nlisUserName, Users.nlisPassword, Users.email, Users.lastLoginDate, Users.createdDate
FROM vw_CustomerGroupAccountDetails RIGHT OUTER JOIN
Organisations ON vw_CustomerGroupAccountDetails.AccountID = CAST(Organisations.id AS nvarchar(50)) RIGHT OUTER JOIN
Users ON Organisations.clientId = Users.uploadedBy
WHERE (Users.canLogin = 1) AND (Users.isDeleted = 0) AND (NOT (Organisations.USR IS NULL)) AND
((vw_CustomerGroupAccountDetails.CustomerGroupID = @CustomerGroupID) OR (@CustomerGroupID IS NULL))
)
那么,当我使用 SqlCommand 的 SqlParameter 从 C# 调用 SQL 函数时,是什么原因导致它需要更长的时间呢?
我正在使用 SQL Server 2000。
我到处搜索,以我能想到的每一种方式,但找不到其他人有同样的问题。