The term "selective expansion" describes a hierarchical query where all the rows at, above, and below a target item are returned. For example, given a data set that looks like this:
PADDED_KEY
---------------
a
a.a
a.b
b
b.a
b.b
b.b.a
b.c
b.c.a
b.c.b
b.c.c
b.c.c.a
b.c.c.b
b.c.c.c
a selective expansion of a target item like "b.c.c" would give us the following rows.
PADDED_KEY
---------------
b
b.c
b.c.c
b.c.c.a
b.c.c.b
b.c.c.c
The tutorials in this section describe various methods for performing a selective expansion. If you are not familiar with hierarchical queries you should review SQL Features Tutorials: Hierarchical Data before proceeding.