I want to check whether the ,entered email id exist or not
When, where? What have you tried? :doh:
I guess you want a feature to check if emailid already exists or not in your application. For that, you need to execute a query with the email id and see if count is greater than zero. If so, it exists.
SELECT COUNT(*) FROM EmailTable WHERE storedEmailIDs = 'checkThisID@Abc.com'