sgrebnov opened a new pull request, #11589: URL: https://github.com/apache/datafusion/pull/11589
Please let me know if you prefer to split this into separate PRs. Combined as they are related/follow the same logic and to avoid resolving conflicts after PRs are merged. ## Which issue does this PR close? PR addresses unparser issues producing invalid sql for MySQL and implements support for `IntervalStyle::MySQL` #### 1. Invalid `CAST(col AS Timestamp)` SQL for MySQL. MySQL [cast function](https://dev.mysql.com/doc/refman/8.4/en/cast-functions.html#function_cast) does not support Timestamp for CAST and requires DATETIME > DATETIME[(M)] Produces a [DATETIME](https://dev.mysql.com/doc/refman/8.4/en/datetime.html) value. If the optional M value is given, it specifies the fractional seconds precision. Timezone information is correctly handled by MySQL when casting with `DATETIME`. #### 2. Unsupported `date_part` function to extract Datetime subfield MySQL does not support **date_part** function so PR introduces configurable option to specify Datetime subfield extraction style for unparsing. Different DBMSs follow different standards; popular ones are: ```sql date_part('YEAR', date '2001-02-16') EXTRACT(YEAR from date '2001-02-16') ``` Some DBMSs, like Postgres, support both, whereas others like MySQL, Amazon Athena require EXTRACT. #### 3. invalid `CAST(col AS BigInt)` SQL for MySQL. MySQL [cast function](https://dev.mysql.com/doc/refman/8.4/en/cast-functions.html#function_cast) does not support BigInt and requires SIGNED for CAST > SIGNED [INTEGER] Produces a signed [BIGINT](https://dev.mysql.com/doc/refman/8.4/en/integer-types.html) value. Note: sqlparser crate does not have Signed type so we use `ast::DataType::Custom` as a workaround ## Rationale for this change PRs implements `IntervalStyle::MySQL` and adds support for alternate formats for Timestamp, Int64, Datetime part unparsing via Dialect customization. ## What changes are included in this PR? Please see above ## Are these changes tested? Manual testing + unit test for each modification. ## Are there any user-facing changes? `CustomDialectBuilder` now supports more options for Dialect customization (Timestamp, Int64 unparsing and Datetime part extraction). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
