Message=ERROR [HY000] [Oracle][ODBC][Ora]ORA-00936: missing

Muralidharan , THANK YOU VERY MUCH FOR YOUR HELP.

yes, I add the schema name now, pfods.MWOHED.
for Oracle's NUMBER, is the C# Datatype Int32?
for Oracle's NUMBER(15,6), is the C# Datatype Int64?

I keep on getting the error message "Error contacting database".

I attached the whole project with the printscreen for the LINQPAD.

In your query, there is no schema name is present but in your LINQPad query it is present.

Schema name added.

 cmd.CommandText = "SELECT VHITNO FROM pfods.MWOHED WHERE VHMFNO ='" + MO_No + "'";

pls see attached file.

Can you please the call stack? that tells you complete call hierarchy.

I'm attached the parameter the query + cmd.ExecuteReader() is changed. We will try without commandbehaviour option.

//Just hardcode the complete query
            cmd.CommandText = "SELECT VHITNO FROM MWOHED WHERE VHMFNO ='" + MO_No + "'";

            //Later include the single quotes in the query.           
            //cmd.Parameters.AddWithValue("@VHMFNO", MO_No);
            //cmd.CommandText = "SELECT VHITNO FROM MWOHED WHERE VHMFNO ='" + @VHMFNO + "'";

            con.Open();
            MessageBox.Show("Connected");
            
            try
            {
                OdbcDataReader reader = cmd.ExecuteReader();
                if (reader.Read())
                {
                    ProductionInfo productioninfo = new ProductionInfo((String)reader["VHITNO"]);
                    return (productioninfo);
                }
                else
                {
                    return null;
                }
            }
            finally
            {
                con.Close();
            }

the error comes from code which contain the try.. finally... it does not go into the try portion of the code, but goes into finally portion of the code.

I try your suggestion as attached, but got the same error:

Hi,
Try this way.

//Just hardcode the complete query
cmd.CommandText = "SELECT VHITNO FROM MWOHED WHERE VHMFNO ='"+MO_No +"'";
            
//Later include the single quotes in the query.
cmd.CommandText = "SELECT VHITNO FROM MWOHED WHERE VHMFNO ='"+@VHMFNO +"'";
cmd.Parameters.AddWithValue("@VHMFNO", MO_No);