[
https://issues.apache.org/jira/browse/DERBY-4401?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12764006#action_12764006
]
Knut Anders Hatlen commented on DERBY-4401:
-------------------------------------------
Some examples with toursdb:
-- Inner join that shows the number of cities in each country
SELECT COUNTRY, COUNT(*) AS NUM
FROM COUNTRIES INNER JOIN CITIES USING (COUNTRY)
GROUP BY COUNTRY ORDER BY NUM
-- Left outer join that shows the same as the previous join, but also includes
countries with no cities in the result
SELECT COUNTRY, COUNT(CITY_ID) AS NUM
FROM COUNTRIES LEFT OUTER JOIN CITIES USING (COUNTRY)
GROUP BY COUNTRY ORDER BY NUM
> Document USING clause in joins
> ------------------------------
>
> Key: DERBY-4401
> URL: https://issues.apache.org/jira/browse/DERBY-4401
> Project: Derby
> Issue Type: Improvement
> Components: Documentation
> Affects Versions: 10.6.0.0
> Reporter: Knut Anders Hatlen
> Priority: Minor
>
> DERBY-4370 made some of the join operations accept a USING clause. This
> should be documented in the reference manual.
> The JOIN operations section talks about "join clause", which should be fine
> since that could mean both ON clause and USING clause.
> The sections INNER JOIN operation, LEFT OUTER JOIN operation and RIGHT OUTER
> JOIN operation need to be updated with the new syntax. We need to replace
> {
> ON booleanExpression
> }
> with
> {
> { ON booleanExpression } |
> { USING ( Simple-column-Name [ , Simple-column-Name ]* ) }
> }
> Perhaps it would make sense to factor out this part of the syntax into a
> separate element JoinSpecification, and explain the meaning of USING there.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
