What I want ot be able to do is enter data into mysql database so that it is encrypted, but still be able to
select * from saiddatebase where encrypteddata ="";

I still want to be able to use the data, but it must be encrypted.

Yes you can if you use the "password" function.
Something like:

SELECT * FROM USERS WHERE PASSWORD = PASSWD('TEST');

Regards.

I don't know if your implementation is through the web with something like PHP, but you'd be better off using MD5 to store passwords. Using a javascript version (available for free online somewhere) to encode the password before transmitting the form to the server keeps passwords from passing in clear text between the browser and the server. You store the MD5 version of their password in your database and when they login you compare the MD5 value in the db and the MD5 value passed by the login form.

Just a suggestion. I don't know how sensative you're login info is. I generally classify login/password information as the highest level of information and no matter what I implement I protect it the best I can.

This is all, of course, if you cannot use SSL. (and combined is even better)