将2个SQL查询合并为一个查询并转换为c#

本文关键字：查询 一个 转换 2个 SQL 合并 | 更新日期: 2023-09-27 18:02:22

我需要将这两个单独的查询合并为一个，因为它效率不高，并将其转换为c# ASP。. NET from Classic ASP

SQL = "SELECT MemID FROM network WHERE userid='"&strTemp&"'"
Set rsNet = Conn.Execute(SQL)
if NOT rsNet.eof then
strList = rsNet("memID")
end if
rsNet.close
set rsNet = Nothing
SQL = "SELECT Distinct userid, username, img1, birthday, gendid, city, state, country, title FROM UserInfo WHERE (userinfo.userid IN (" & strList & ")) "
Set rsView = Server.CreateObject("ADODB.Recordset")
rsView.Open SQL, Conn, adOpenKeyset, adLockReadOnly
if NOT rsView.EOF then
arrN = rsView.getrows()
end if
rsView.close
set rsview = nothing

将2个SQL查询合并为一个查询并转换为c#

我不知道c#，但SQL去一个经典的连接…

SELECT userid, username, img1, birthday, gendid, city, state, country, title
FROM UserInfo
JOIN network
ON network.MemID = userinfo.userid
AND network.userid = :inputUserId

您应该只需要DISTINCT，如果由于某种原因，您有非唯一的行。

DataTable dtTable = null;
using (SqlConnection oConn = new SqlConnection("Your connection string"))
{
   string strQuery = @"SELECT Distinct userid, username, img1, birthday, gendid, city, state, country, title 
   FROM UserInfo 
   WHERE userinfo.userid IN 
   (
      SELECT MemID 
      FROM network
      WHERE userid= @userid 
    )";
   SqlDataAdapter oDataAdapter = new SqlDataAdapter(strQuery, oConn);
   oDataAdapter.Fill(dtTable, "TableName");
}

@X-Zero的select很好——如果您使用microsoft (sql-server)，则参数将是@uinputUserID，而不是:inputUserId。

否则，将其转换为asp.net(使用c#)取决于您想使用的控件—dataset, datatable, datasource, datareader等…@Mr。的数据表是一个很好的方法，但是你需要将它绑定到任何正在使用它的控件。

试试这个(我包括using语句，以防您不熟悉ADO.NET使用的权利语句):

using System.Data;
using System.Data.SqlClient
public DataTable GetUserDetails(int userID)
{
    DataTable dTable = new DataTable();
    using (SqlConnection con = new SqlConnection(<your connection string>))
    {
        con.Open();
        SqlCommand cmd = new SqlCommand();
        cmd.Parameters.Add(new SqlParameter("@userid", userID);
        cmd.Text = "SELECT DISTINCT u.userid, u.username, u.img1, u.birthday, u.genid, u.city, u.state, u.country, u.title FROM UserInfo u JOIN Network n ON u.userid = n.userid WHERE n.userid = ?";
        cmd.CommandType = CommandType.Text;
        cmd.Connection = con;
        SqlDataAdapter da = new SqlDataAdapter(cmd);        
        da.Fill(dTable);
    }
    return dTable;
}

这并不像其他答案想象的那么简单，因为它看起来像MemId是一个逗号分隔的字符串字段(糟糕的数据库设计)。因此，你必须使用动态SQL在…动态SQL . 

using (SqlConnection conn = new SqlConnection(@"ConnectionStringHere"))
{
    conn.Open();
    IDbCommand cmd = conn.CreateCommand();
    cmd.CommandText = @"
        DECLARE @sql nvarchar(MAX)
        SET @sql = '
            SELECT DISTINCT
                userid, username, img1, birthday,
                            gendid, city, state, country, title 
                FROM UserInfo 
                WHERE UserId IN 
                (' + (SELECT MemID FROM network WHERE UserId = @userId) + ')'
        EXEC(@sql)";
    IDbDataParameter param = cmd.CreateParameter();
    param.DbType = DbType.String;
    param.Value = "12345"; // TODO
    param.ParameterName = "@userId";
    cmd.Parameters.Add(param);
    IDataReader dr = null;
    try
    {
        dr = cmd.ExecuteReader();
        // TODO: Process result set
    }
    finally
    {
        if (dr != null)
            dr.Close();
    }
}
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