want to get value of guid column in database table from SELECT Query ???

hi,

I have a  database table called  Booking.
BookingId - p-k int
Name - nvar char
CustomerId - GUID
ValidationId - GUID

Using a SELECT Query,  GetCustomerIdByValidationId - I want
to get the value of type GUID in the CustomerId column
Where ValidationId =@ValidationId

I then want to use the value in another statement to send an email

string connString = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"; string cmdText = "SELECT * FROM BOOKING WHERE ValidationId=@ValidationId;";
using (SqlConnection conn = new SqlConnection(connString)) { conn.Open(); // Open DB connection.
using (SqlCommand cmd = new SqlCommand(cmdText, conn)) { cmd.Parameters.AddWithValue("@ValidationId", inv); // Add the SQL parameter. SqlDataAdapter da=new SqlDataAdapter(cmd); DataTable dt=new DataTabl ...