kiszk commented on a change in pull request #27489: [WIP][SPARK-30703][SQL][DOCS] Add a document for the ANSI mode URL: https://github.com/apache/spark/pull/27489#discussion_r376311138
########## File path: docs/sql-ref-ansi-compliance.md ########## @@ -19,6 +19,87 @@ license: | limitations under the License. --- +Spark SQL has two options to comply with the SQL standard: `spark.sql.ansi.enabled` and `spark.sql.storeAssignmentPolicy`. +When `spark.sql.ansi.enabled` is set to `true` (`false` by default), Spark SQL follows the standard in basic behaviours (e.g., arithmetic operations, type conversion, and SQL parsing). +Moreover, Spark SQL has an independent option to control implicit casting behaviours when inserting rows in a table. +The casting behaviours are defined as store assignment rules in the standard. +When `spark.sql.storeAssignmentPolicy` is set to `ANSI`, Spark SQL complies with the ANSI store assignment rules and this setting is enabled by default. + +The following subsections present behaviour changes in arithmetic operations, type conversions, and SQL parsing when the ANSI mode enabled. + +### Arithmetic Operations + +In Spark SQL, arithmetic operations performed on numeric types (with the exception of decimal) are not checked for overflow by default. +This means that in case an operation causes an overflow, the result is the same that the same operation returns in a Java/Scala program (eg. if the sum of 2 integers is higher than the maximum value representable, the result is a negative number). Review comment: nit: `eg.` -> `e.g.` ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
