The invasion unfolded so rapidly that Denmark didn't have time to declare war on Germany. Danish military resistance was limited though spirited with the Danes knocking out many German armored cars and disabling a few tanks; the military resistance however lasted no more than six hours. This was one of the shortest armed invasions of the war. In all between 13 and 49 Danes were killed; sources vary widely but the number is generally agreed upon as 16.
With this, Denmark was occupied by the Germans until the end of the war.
Now for the walk around of the m.1923:
In all, some 850 members of the Danish resistance died at the hands of the Germans.