如何在存储过程的 WHERE 子句中使用类型数据表答案

【问题标题】：How to use a type datatable in WHERE clause of a stored procedure如何在存储过程的 WHERE 子句中使用类型数据表
【发布时间】：2016-08-14 15:05:25
【问题描述】：

基本上我有一个 C# 应用程序，它将创建一个数据表并将数据表作为存储过程传递。然而，这一切都有效；我要做的是向传入的数据表添加逻辑。

例如，在下面的测试中，您将看到一个名为 RealInsertNewRecords 的过程；这个尝试确保不会发生重复的主键违规，但我收到错误

必须声明标量变量“@dataTable”

以下是一个完整的测试，感谢任何帮助。谢谢！

澄清存储过程RealInsertNewRecords是什么不起作用

using System;
using System.Data;
using System.Data.SqlClient;

namespace testApp
{
    class Program
    {
        static void Main(string[] args)
        {
            string SQLServer = @"";
            SqlConnection sqlCon = new SqlConnection("Data Source=" + SQLServer + ";Initial Catalog=myTestDB;Integrated Security=SSPI;");

            sqlCon.Open();
            InsertNewRecords(sqlCon, testTable1());
            InsertNewRecords(sqlCon, testTable2());
            sqlCon.Dispose();
        }

        public static DataTable testTable1()
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("myTestPK");

            string[] items = new string[] { "apples", "pears" };

            for (int i = 0; i < items.Length; i++)
            {
                DataRow dr = dt.NewRow();
                dr[0] = items[i];
                dt.Rows.Add(dr);
            }

            return dt;
        }

        public static DataTable testTable2()
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("myTestPK");

            string[] items = new string[] { "apples", "pears", "grapes" };

            for (int i = 0; i < items.Length; i++)
            {
                DataRow dr = dt.NewRow();
                dr[0] = items[i];
                dt.Rows.Add(dr);
            }

            return dt;
        }

        public static void InsertNewRecords(SqlConnection sqlCon, DataTable parameterTable)
        {
            SqlCommand cmd = new SqlCommand();
            cmd.CommandText = "InsertNewRecords";
            cmd.Parameters.AddWithValue("dataTable", parameterTable);
            cmd.Connection = sqlCon;
            cmd.CommandType = CommandType.StoredProcedure;

            cmd.ExecuteNonQuery();
        }
    }
}

SQL

if exists (select 'x' from sys.databases where [name] = 'myTestDB')
begin
     drop database myTestDB;
end

Create database myTestDB;
GO

USE [myTestDB]
GO

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

CREATE TABLE [dbo].[myTable]
(
    [myTestPK] [nvarchar](50) NOT NULL,

    CONSTRAINT [PK_myTable] 
        PRIMARY KEY CLUSTERED ([myTestPK] ASC)
           WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, 
                 IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, 
                 ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

create Type [dbo].myTableParameters as table
(
    myTestPK nvarchar(10)
)
go

create procedure InsertNewRecords(@dataTable [dbo].myTableParameters readonly)
as
begin
    insert into myTable
        select * from @dataTable;
end
go

--This is what i really want to do!
create procedure RealInsertNewRecords(@dataTable [dbo].myTableParameters readonly)
as
begin
    insert into myTable
        select * 
        from @dataTable
        where not exists (select 'x' 
                          from myTable m 
                          where m.myTestPK = @dataTable.myTestPK)
end

【问题讨论】：

标签： c# sql-server stored-procedures datatable

【解决方案1】：

您的问题与使用表值参数无关。而是您的 SQL 是错误的。

insert into myTable
    select * 
    from @dataTable
    where not exists (select 'x' 
                      from myTable m 
                      where m.myTestPK = @dataTable.myTestPK) <-- this line isn't legal

您应该使用 MERGE 语句。

MERGE INTO MyTable t USING @dataTable s ON t.myTestPK = s.myTestPK
WHEN NOT MATCHED THEN INSERT (myTestPK) VALUES (s.myTestPK)
; <-- the semicolon is required

https://msdn.microsoft.com/en-us/library/bb510625.aspx

我总是将我的表命名为 t 为目标，s 为源。我发现它更容易跟踪哪个是哪个。

【讨论】：

【解决方案2】：

这不是最好的方法，但我只是想出了一种方法来处理它。而不是直接访问 DataTable 插入到临时表中。

create procedure InsertNewRecords(@dataTable [dbo].myTableParameters readonly)
as
begin
select * into #InsertNewRecords
from @dataTable;

insert into myTable
select * from #InsertNewRecords
where not exists (select 'x' from [myTable] where [myTable].myTestPK = #InsertNewRecords.myTestPK);
end
go

【讨论】：