Myth Conceptions by Robert Asprin
Skeeve is an apprentice Wizard who tried to get a job as a court magician. He and his demon mentor (who is posing as his apprentice) are able to convince them to hire him. Then they realize the kingdom wants the wizard to help defeat some enemies. He eventually meets the enemy army and finds the only reason they are fighting is due to debts they have. Instead of fighting, Skeeve helps make them disappear, making everyone happy without a fight. The plot is simple, but the way they go about it is what brings the fun.
Myth-Chief is a fantasy, detective, comedy work that is deep in a series of books. Perhaps if I started earlier in the series I might have found this more intriguing. Instead I had trouble following what was going on and why I should care about it. Some detectives were having a contest to solve a case and be leaders. They did stuff but cared too much about themselves, so another person became the leader. They seemed to have solved the case and have some funny things happen on the way.