Question

我有：

 string commandText = @"SELECT cn.companyName from Companies cn 
               INNER JOIN KeyProcesses uc ON uc.companyId = cn.companyId  
               WHERE uc.description like '%" + ProcessInputClause + "%';";

 string addr = @"SELECT address FROM Companies where companyName = @companyName";

执行我尝试过：

SqlCommand sqlCmd = new SqlCommand();
sqlCmd.CommandText = commandText;
sqlCmd.Parameters.Clear();
string connectionString = ConfigurationSettings.AppSettings["connectionString"];
using (SqlConnection connection = new SqlConnection(connectionString))
{
   SqlCommand command = new SqlCommand(commandText, connection);
   try
   {
       connection.Open();
       sqlCmd = new SqlCommand(sqlCmd.CommandText, connection);
       SqlDataReader sqlReader = sqlCmd.ExecuteReader();
       DataTable dt = new DataTable();

       sqlReader.Read();
       dt.Load(sqlReader);
       Label1.Text = dt.Rows[0][0].ToString();
       sqlCmd.CommandText = addr;
       SqlCmd.Parameters.AddWithValue("@companyName", "namehere");
       SqlDataReader addressReader = sqlCmd.ExecuteReader();
       addressReader.Read();
       Label1.Text = Label1.Text + addressReader["address"].ToString() + addressReader.GetValue(1).ToString() + addressReader.GetString(0) + addressReader.GetString(1);

我只能获得第一个要执行的sql，并将companyName获取为Label1.text。但看起来第二个executeReade（）没有给我任何结果，虽然我单独尝试了查询！我也尝试了combine命令文本并使用nextresult但没有运气。你能帮我解决一下如何成功执行这两个命令吗？ Ps：添加了调用addressReader.Read（）;我忘了复制这个，试过这个但没有结果！

Answer 1

首先要做的是参数化第一个查询; p

之后，需要更改的所有内容是实际使用第二个阅读器：

using(var addressReader = sqlCmd.ExecuteReader()) {
    if(addressReader.Read()) {
        Label1.Text = Label1.Text + addressReader["address"].ToString()
         + addressReader.GetValue(1).ToString() + addressReader.GetString(0)
         + addressReader.GetString(1);
    }
}

编辑：删除它，因为它不适用，因为这两个查询是分层的

<击> 你可以在单个sql操作（NextResult()等）中执行两个选择，但我不确定dt.Load是否可以正常运行;不过值得一试：

sqlCommand.CommandText = @" SELECT cn.companyName from Companies cn INNER JOIN KeyProcesses uc ON uc.companyId = cn.companyId WHERE uc.description like '%' + @description+ '%'; SELECT address FROM Companies where companyName = @companyName;"; sqlCommand.Parameters.AddWithValue("description", ProcessInputClause); sqlCommand.Parameters.AddWithValue("companyName", "namehere"); using(var reader = sqlCommand.ExecuteReader()) { dt.Load(reader); if(reader.NextResult() && reader.Read()) { Label1.Text = Label1.Text + reader["address"].ToString() + reader.GetValue(1).ToString() + reader.GetString(0) + reader.GetString(1); } }

<击>

由于查询之间存在依赖关系，并且地址是公司记录的一部分，我只会这样做：

@"SELECT cn.companyName, cn.Address from Companies cn INNER JOIN KeyProcesses uc ON uc.companyId = cn.companyId WHERE uc.description like '%" + @description + "%';";

获取两个值的单个查询。您可以使用现有的dt.Load来访问它，从第一列获取名称，从第二列获取地址 - 但坦率地说，我是＆＃34; dapper＆＃34;的忠实粉丝，所以我＆＃ 39; d这样做：

class Company { public string CompanyName {get;set;} public string Address {get;set;} } ... var rows = conn.Query<Company>( @"SELECT cn.companyName, cn.Address from Companies cn INNER JOIN KeyProcesses uc ON uc.companyId = cn.companyId WHERE uc.description like '%" + @description + "%';", new { description = ProcessInputClause }).ToList();

然后迭代rows：

foreach(var row in rows) { string name = row.CompanyName; string address = row.Address; // ... }

或者，如果您不想申报类型：

var rows = conn.Query( @"SELECT cn.companyName, cn.Address from Companies cn INNER JOIN KeyProcesses uc ON uc.companyId = cn.companyId WHERE uc.description like '%" + @description + "%';", new { description = ProcessInputClause }).ToList(); foreach(var row in rows) { string name = row.companyName; // yes, this works string address = row.Address; // ... }

在涉及多个表的场景中，您可以使用表变量作为连接的基础：

declare @ids table (CompanyId int not null) insert @ids (CompanyId) select companyId from Companies cn INNER JOIN KeyProcesses uc ON uc.companyId = cn.companyId WHERE uc.description like '%" + @description + "%'; select cn.CompanyName, cn.Address from @ids #i inner join Companies cn on cn.CompanyId = #i.CompanyId select /* other stuff */ from @ids #i inner join /* other tables */ select /* yet more other stuff */ from @ids #i inner join /* yet more other tables */

Answer 2

您可以将两个命令放在字符串数组上，并在命令中执行foreach语句命令。

像这样：

string command1 = @"SELECT cn.companyName from Companies cn 
               INNER JOIN KeyProcesses uc ON uc.companyId = cn.companyId  
               WHERE uc.description like '%" + ProcessInputClause + "%';";
string command2 = @"SELECT address FROM Companies where companyName = @companyName";

string[] commands  = new string[2];
        commands.SetValue(command1 , 0);
        commands.SetValue(command2 , 1);

然后：

Foreach(string command in commands)
{
    SqlCommand c= new SqlCommand(command , connection);
    //do the rest
}

Answer 3

使用DataSet而不是Datatable

DataSet ds = new DataSet();

SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["connectionString"].ConnectionString);


SqlDataAdapter da = new SqlDataAdapter(qry, connection);

da.Fill(ds);

如何在asp.net中执行多个sql命令

3 个答案: