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https://issues.apache.org/jira/browse/CASSANDRA-2474?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13087705#comment-13087705
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Jonathan Ellis commented on CASSANDRA-2474:
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bq. SELECT transposed(column) FROM foo WHERE key=X
Can we just write transposed() then instead of implying that there's actually a
single column we're doing this to?
bq. You could then also do supercol slices like transposed(column, start, end)
This isn't much of an improvement over the old slice syntax, from a CQL
perspective. Here's why. If we have "real" WHERE clauses we get all the
benefits of regularity that implies: we can get "traditional" slices
{code}
SELECT transposed() FROM foo WHERE key=X AND column >= X AND column <= Y
{code}
Or "paging" style (start-exclusive), possibly the single most-requested slicing
feature:
{code}
SELECT transposed() FROM foo WHERE key=X AND column > X AND column <= Y
{code}
No special syntax needed for count(), other than I'm not sure we want to go
full-on subquery here. The HQL options don't look great. Maybe we just add a
transposed_count() function too):
{code}
SELECT count(*) FROM
(SELECT transposed() FROM foo WHERE key=X AND column > X AND column <= Y)
{code}
More natural support for just once slice "endpoint":
{code}
SELECT transposed() FROM foo WHERE key=X AND column >= X
{code}
Multi-row slicing:
{code}
SELECT transposed() FROM foo WHERE key IN (X, Y) AND column >= X AND column <= Y
{code}
Multi-slice from single row (CASSANDRA-2710):
{code}
SELECT transposed() FROM foo WHERE key=X AND ((column >= X AND column <= Y) OR
(column >= A AND column <= B))
{code}
Composite column support (i.e., first-part-of-column-name is exactly X):
{code}
SELECT transposed() FROM foo WHERE key=X AND column=X
{code}
Future proof against hypothetical future CQL support for functions:
{code}
SELECT transposed() FROM foo WHERE key=X AND sqrt(column) < X
{code}
... and of course combinations of the above. Adding functions for even just
the examples here would be ugly, let alone further mix-and-matching.
> CQL support for compound columns
> --------------------------------
>
> Key: CASSANDRA-2474
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2474
> Project: Cassandra
> Issue Type: Sub-task
> Components: API, Core
> Reporter: Eric Evans
> Labels: cql
> Fix For: 1.0
>
>
> For the most part, this boils down to supporting the specification of
> compound column names (the CQL syntax is colon-delimted terms), and then
> teaching the decoders (drivers) to create structures from the results.
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