What was the difference between the Pharisees and Sadducees?

Jesus often encountered "Pharisees" and "Sadducees". For example, >34 Hearing that Jesus had silenced the **Sadducees**, the **Pharisees** got together. 35 One of them, an expert in the law, tested him with this question: 36 “Teacher, which is the greatest commandment in the Law?” (Matthew 22:34-36) From a Christian perspective, **Who were they and how did they differ?**