使用另一个数据库的值从一个数据库中搜索 [英] Search from one database using the values of another database

问题描述

我有两个数据库，我正在搜索所有来自database1的custId，并且我需要从数据库2中检索完整的信息。



作为custid将有多个值（比如说我有10个custid，我需要数据库2中的所有客户信息。



这是我的C＃代码：

I have two database first I am searching all custId from database1 and for all that custId I need to retrive their complete infirmation from database 2.

As custid will have more than one value ( say 10 custid I have and I need all customer info from database 2.

Here is my C# code:

using System.Data.SqlClient;

    // .....

    string queryString = "Select custID from Table1"; 
    String TempCustID;

    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        SqlCommand command = new SqlCommand(queryString, connection);
        connection.Open();
        SqlDataReader reader = command.ExecuteReader();
        
        while (reader.Read())
        {
          if (!reader.IsDBNull(0))
          {
             TempCustID = reader[0].ToString();
              
            // Here I need to connect to other database and use TempCustID 
            // variable to search in a Table in DB2
            // And display values in datagridview
            
          }
        }
        reader.Close();
    }

推荐答案

通常 join语句 [ ^ ]用于这种情况。

Usually join statement[^] is used in such of situations.

Select t1.custID, t2.TempCustId
From [dbo1].Table1 AS t1 INNER JOIN [dbo2].Table1 AS t2 ON t1.CustId = t2.TempCustId

以上查询返回记录集，其中 CustId 字段等于 TempCustId 字段。有关详细信息，请参阅： SQL联接的可视化表示 [ ^ ]

Above query returns recordset where CustId field is equal to TempCustId field. For further information, please see: Visual Representation of SQL Joins[^]

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