Crystal is easiest to use if you don't write the syntax yourself. Let Crystal worry about how it all works. When you create a new report, it lets you pick the tables you want to print from. Then it lets you link them together to create the JOIN statements. It uses this information to build your SQL statement. That's all you need to do. If, for some reason, you need more complex SQL, you can use the menu option View SQL Query to see how Crystal built the SQl for your database and then use that as a basis for how to write your own syntax. And if you need to write a WHERE clause, use the record selection formula expert. I bet that 99% of your reports can be built without you writing any SQL.

Since you're new to Crystal Reports, you would probably benefit from checking out my Encylcopedia book. It has numerous tutorials in it and two chapters of how to best use SQL in your reports. You can find out more about my books at Amazon.com or reading the Crystal Reports eBooks online.