START WITH and CONNECT BY keywords. Have a quick look at this Oracle article for more details.Thanks to ITwise and DbMotive for the great tip!
Thursday, June 7, 2007
Oracle support for hierarchical queries
Most of us already encountered the problem of walking through a tree-like structure in database table. Imagine a PERSON table with parent-child relationship, and we want to retrieve all descendants of a person quickly. In plain JDBC and standard SQL, you'll need to write yourself a recursive function and perform multiple requests on your favorite database. Good news for users of Oracle 10g databases: Oracle SQL has extensions to fetch all descendants in one single query! You just need to use the
Thanks to ITwise and DbMotive for the great tip!
Thanks to ITwise and DbMotive for the great tip!
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Take care not to forget the "PRIOR" keyword after the "CONNECT BY" segment. It hangs your execution call, instead of exiting with some descent error message.
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