Witch Is Best?

Hello, i have a table called Mail, inside of this table are all the user mailmessages, now i want to display to the user how many messages he has, should i use:

SELECT count(*) FROM mailmessages WHERE (username = @UserName)

or

Should i create a table with a field named 'mailmessages' for every user, then in this table i update the 'mailmessages' whenever the user deletes or recieves a new message.

witch is the best option to use, lets assume that we have afew million mailmessages? performace gains? fastest?

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