如何在sql查询中传递动态值

本文关键字：动态 查询 sql | 更新日期: 2023-09-27 18:24:41

int i = int.Parse(rid);
SqlConnection thisconnection = new SqlConnection(@"Data Source=.'SQLEXPRESS;AttachDbFilename=D:'lagenius'JIvandhara ngo'JIvandhara ngo'ngo.mdf;Integrated Security=True;User Instance=True");
thisconnection.Open();
string st = ("select  receipt_no, name, rupees, pay_by, date from receipt_info where receipt_no = 4");
DataSet thisdataset = new DataSet();
//string cmdtext = "select * from receipt_info where receipt_no =='" + i + "'";
SqlCommand cmd = new  SqlCommand(st, thisconnection);
SqlDataAdapter data_ad = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
data_ad.Fill(dt);

如何在sql查询中传递动态值

string st = ("select  receipt_no, name, rupees, pay_by, date from receipt_info where receipt_no =" + i);

首先，您应该使用参数重写您的语句

string st = "select  receipt_no, name, rupees, pay_by, date from receipt_info where receipt_no = @Receipt_Number";

当你创建了你的SqlCommand-你应该添加参数@Receipt_Number到它

cmd.Parameters.Add("@Receipt_Number", SqlDbType.Int);
cmd.Parameters["@Receipt_Number"].Value = i;

发送参数化查询时，应使用SqlParameter。有关如何使用它们的示例，请访问http://www.dotnetperls.com/sqlparameter

基本上，您可以使用占位符构建查询，并使用SqlCommands Parameters属性填充它们。

int searchId = 4;
string connectionString = @"Data Source=.'SQLEXPRESS;AttachDbFilename=D:'lagenius'JIvandhara ngo'JIvandhara ngo'ngo.mdf;Integrated Security=True;User Instance=True"
using (SqlConnection connection = new SqlConnection(connectionString)) {
    connection.Open();
    using (SqlCommand command = new SqlCommand(
        "select  receipt_no, name, rupees, pay_by, date " +
        "from receipt_info where receipt_no = @Id", connection))
    {
        command.Parameters.Add(new SqlParameter("Id", searchId));
        SqlDataReader reader = command.ExecuteReader();
        while (reader.Read())
        {
        }
    }
}

string st = string.Format("select receipt_no, name, rupees, pay_by, date from receipt_info where receipt_no = {0}",i);
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