execute a select count sql in c#

Question

I am trying to execute a simple sql select statement using C# and I want to return the number of rows. What is the correct syntax. SELECT Count(*) FROM InvData

Ananth G · Answer

using System.Data.Odbc public static string ReadData( string connectionString) { string objQuery= SELECT count(*) from INVData ; string output=  ; using (OdbcConnection objConn= new OdbcConnection(connectionString)) { OdbcCommand objCmd= new OdbcCommand(objQuery objConn); objConn.Open(); OdbcDataReader objReader= objCmd.ExecuteReader(); while (objReader.Read()) { output=objReader[0].ToString(); objReader.Close(); } objConn.Close(); } return output; } u can use like this

Ifour Hiren · Answer

cmd.CommandText = SELECT COUNT(*) FROM InvData; Int32 count = (Int32) cmd.ExecuteScalar(); above code helps you to make it working.

Ryan Alford · Answer

this is more of an edit to Jeff's post. Not really necessary to use a DataReader object if just returning one column. public static void ReadData ( string connectionString ) { string queryString = SELECT count(*) from INV ; using ( OdbcConnection connection = new OdbcConnection ( connectionString )) { OdbcCommand command = new OdbcCommand ( queryString  connection ); connection . Open (); int count = command . ExecuteScalar (); Console . WriteLine ( Count is: {0}  count ); } } ExecuteScalar() returns the first column of the first record. Since we are only return one column of one record it is the perfect solution. Also since you didn't state with database you were using we chose to use the ODBC connection. If you are using SQL Server you can use SqlConnection and SqlCommand instead.

Ron · Answer

Try this. private void button2_Click(object sender EventArgs e) { SqlConnection myConnectionAdd = null; DataSet myDataSetAdd = new DataSet(); myConnectionAdd = new SqlConnection(Data Source=YourSource Catalog=YourCatalog;Integrated Security=True); string mySqlInsert = SELECT count(*) FROM dbo.Customers; SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter(); mySqlDataAdapter.SelectCommand = new SqlCommand(mySqlInsert myConnectionAdd); mySqlDataAdapter.Fill(myDataSetAdd count(*)); dataGridView1.DataSource = myDataSetAdd.Tables[count(*)]; myConnectionAdd.Close(); }

Jeff Johnson · Answer

Try the snippet below you may need to research some of the other classes to get your connectionString (DSN= etc) but this worked for me. using System.Data.Odbc public static void ReadData( string connectionString) { string queryString = SELECT count(*) from INV ; using (OdbcConnection connection = new OdbcConnection(connectionString)) { OdbcCommand command = new OdbcCommand(queryString connection); connection.Open(); // Execute the DataReader and access the data. OdbcDataReader reader = command.ExecuteReader(); while (reader.Read()) { Console.WriteLine( CustomerID={0  reader[0]); // Call Close when done reading. reader.Close();