How run query if any of the text boxes have value

hi

Suppose I have three text boxes One is for user name, second for profile name and third one is for date of birth.

All I want to run query if one or more text boxes have value.

For example if profile name text box is filled then query should have where caluse with value of profile name text box. 

Ofcourse there can be two textboxes filled like user name and date of birth text boxes have values then query should run on the basis of both text boxes.