Really? I never knew that! That's very interesting. I guess the police don't need a search warrant, then to search a company's premises? I mean, you said a company doesn't have "rights", right?
The fourth amendment is styled as a right of the people. The police would still need a warrant to search unless the search fell within an exception to the warrant requirement. (For example if a business were to display contraband in plain view.) A search warrant is based on probable cause that a person has committed a crime and evidence/contraband may be present. A corporation cannot commit a crime; the people who operate the corporation would be responsible for a corporation's criminal acts.
There are some exceptions. For example an inspector who is charged with enforcing safety rules has the ability to get a warrant in order to discharge his duty if denied entry to a place that he is lawfully charged with inspecting.