Conversation so far:
What was Judy Garland's role in The Wizard of Oz?
Dorothy Gale.
Did she sing any songs?
"Over the Rainbow".
What was The  Wizard of Oz based on ?
a film based on the 1900 children's book by L.
Frank Baum.
How long did it take to complete the movie?
Shooting commenced on October 13, 1938, and was completed on March 16, 1939.

Question: Was the Wizard of Oz successful?
Self-contained rewrite: Was the Wizard of Oz a commercial success?