Chris Baynes created CALCITE-1841:
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Summary: Create handlers for Jdbc dialect specific generated sql
Key: CALCITE-1841
URL: https://issues.apache.org/jira/browse/CALCITE-1841
Project: Calcite
Issue Type: Improvement
Components: jdbc-adapter
Reporter: Chris Baynes
Assignee: Julian Hyde
Currently the only way to generate different sql for dialects is to switch on
the dialect in the unparse method. This is used quite heavily in e.g.
SqlFloorFunction, but there are also switches in:
* SUBSTRING()
* SqlDateLiteral quoting
* SqlTimestampLiteral quoting
* Dialects using different interval literals (e.g. Hsqldb uses YYYY & MM rather
than YEAR & MONTH)
* limit/offset construction
* mysql isnull function
* type differences (*)
It would be great to have dialect specific handlers to deal with these, making
testing & addition of new handlers (new dialects, or new overrides for a given
function) much easier in the future.
One suggested path to approach this:
https://issues.apache.org/jira/browse/CALCITE-1798?focusedCommentId=16031609&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16031609
(*) There is a comment in SqlImplementor that reads "MySQL doesn't have a
VARCHAR type, only CHAR.". Not sure if this was for a very old version of
mysql, but it's certainly not true anymore.
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