Database Reference
In-Depth Information
Figure 4.12
A Hierarchical
Query.
We can improve on the query result from Figure 4.12 by altering it
accordingly, showing the result in Figure 4.13.
SELECT LEVEL
, (SELECT NAME FROM INSTRUMENT
WHERE INSTRUMENT_ID = I.SECTION_ID) "Section"
, I.NAME AS Instrument
Figure 4.13
A Meaningful
Hierarchical
Query.
