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roseindia. They have some excellent examples.
Did you take a look at the examples in the online reference guide I posted. Chapter 21. I found them very easy.
Perhaps, to really appreciate and internalize you need to read some basic SQL stuff and think how do you actually use your query results in your business code.
1. Learn little SQL basics, joins, unions, group by, how to minize query results, define fetch sizes etc., How do you actually obtain children. Have example tables like parent, child and foreign key in child table.
2. Start off with simple employee-manager relationship.
3. Learn some normalization. learn the examples.
These should ease things up. Do let us know how you are progressing.