How to convert a number(13) to string in c#

Implicit Conversion: You can try converting the NUMBER column in your Oracle database to a string using the TO_CHAR() function within your SQL query. This converts the numeric value to a string for comparison.

SELECT *
FROM your_table
WHERE TO_CHAR(your_number_column) = 'your_string_value';

This way, the NUMBER column is converted to a string in the SQL query itself.

Explicit Conversion in C#: When retrieving data from the NUMBER column in C#, ensure that you explicitly convert it to a string before comparison

using Oracle.ManagedDataAccess.Client; // Namespace for Oracle Managed Data Access

class OracleNumberToStringComparison
{
    static void Main()
    {
        string connectionString = "Your_Oracle_Connection_String"; // Replace with your connection string

        using (OracleConnection connection = new OracleConnection(connectionString))
        {
            string queryString = "SELECT your_number_column FROM your_table WHERE your_condition";

            using (OracleCommand command = new OracleCommand(queryString, connection))
            {
                connection.Open();

                // Execute the query and retrieve the NUMBER column
                object result = command.ExecuteScalar();

                if (result != null && result != DBNull.Value)
                {
                    // Convert the retrieved NUMBER to string for comparison
                    decimal yourNumber = Convert.ToDecimal(result);
                    string yourNumberAsString = yourNumber.ToString();

                    // Your string value for comparison
                    string yourStringValue = "your_string_value";

                    // Compare the converted string with your string value
                    if (yourNumberAsString.Equals(yourStringValue))
                    {
                        // Comparison logic if they are equal
                        Console.WriteLine("The NUMBER column value is equal to the string value.");
                    }
                    else
                    {
                        // Comparison logic if they are not equal
                        Console.WriteLine("The NUMBER column value is not equal to the string value.");
                    }
                }
                else
                {
                    Console.WriteLine("No data retrieved from the query.");
                }
            }
        }
    }
}

Replace "Your_Oracle_Connection_String" with your actual connection string to connect to your Oracle database. Also, adjust your_table, your_number_column, and your_condition to match your specific table/column names and conditions for the comparison.

This code demonstrates how to convert the retrieved NUMBER value from Oracle to a string in C# explicitly and then compare it with another string value. Adjust the comparison logic as needed for your specific requirements.

Amit thanks for the reply still i am getting value was eigher too large or too small for an unsigned byte remember my parameter of mthod is string but the type of countrypopulation in db is (Number,13) my string contains exact 13 digits 

Try this:

string count = "523456789";
if (decimal.TryParse(count, out decimal numericValue))
{
    var ccc = (from ss in db.countries
               where ss.countryPopulation == numericValue
               select ss).FirstOrDefault();
}
else
{
    Console.WriteLine("Invalid numeric input");
}

thank jayraj I am doing it already but still getting the same error inconsistent datatypes: expected - got NCLOB

here is my linq 

var ccc=(from ss in db.countries where (ss.countryPopulation).tostring()==count select ss).firstorDefault

countryPopulaiton is of number 13 in oracle and count is parameter of method as string

To compare an Oracle NUMBER column with a string in C#, you need to convert the NUMBER value to a string before performing the comparison. The exception you are encountering is likely due to the mismatch between the data types.

Here's an example of how you can convert the NUMBER column to a string in C#:

using Oracle.ManagedDataAccess.Client;

// Assuming you have a connection to the Oracle database
using (OracleConnection connection = new OracleConnection(connectionString))
{
    connection.Open();

    // Assuming you have a command to retrieve the data from the Oracle database
    using (OracleCommand command = new OracleCommand("SELECT your_number_column FROM your_table", connection))
    {
        using (OracleDataReader reader = command.ExecuteReader())
        {
            while (reader.Read())
            {
                // Convert the NUMBER value to a string
                string numberAsString = reader.GetDecimal(0).ToString();

                // Perform the comparison with the string value
                string yourString = "your string value";
                if (numberAsString == yourString)
                {
                    // Perform the desired action
                }
            }
        }
    }
}

In the above example, we retrieve the NUMBER value from the Oracle database using OracleDataReader and convert it to a string using the GetDecimal method. Then, we can compare it with the desired string value using the == operator.

Make sure to replace your_number_column, your_table, your_string_value, and connectionString with the appropriate values for your specific use case.