title: Create Column in Table after a Condition is Met
body: <p>I am just learning Databases and going with MySQL.  I am creating a C# form project to act a a rewards tracker.   The way this reqards system is used by the company I am building it for is that every $10 is a point. Like 19.99 is still just one point.  I got that logic down and know how to implement that.  What I want to do is create a table for transaction history. Where the table expands and starts with the Account# as the primary key and will also have transaction 1 as the start of the table.  After the first transaction I want to know how to Add a column for another transaction if transaction 1 is already filled.  How would I go about doing this in MySQL first and if anyone is feeling especially generous, how would I do this in C#?</p>
  
  <p>I think this question is too specific, but my Google-Fu was not strong enough today. </p>
  
  <p>Edit: I think I also want to make the transaction with as a string, with the total cost of the transaction and a timestamp.
  Otherwise I think I would have to create a too many columns and overload the database</p>