Fix (issuse: #104) : Cast error when 'set password'

[joeCarf]

Problems solved in this PR

issuse: https://github.com/ApsaraDB/galaxysql/issues/104

Changes proposed in this PR

Tests

• [ ] Unit test
• [ ] DML_DDL test

Release note

None

[joeCarf]

@Oldbread3 PTAL:)

[Oldbread3]

Will this fix cause exception for statement like set password for yejr@'%' = password('xx'); ?

[Oldbread3]

Amend use name at code path below might be the proper way to fix this issue. https://github.com/polardb/polardbx-sql/blob/ffd596b88044465c0bfdcda7d19a2882fe0acc89/polardbx-parser/src/main/java/com/alibaba/polardbx/druid/sql/dialect/mysql/parser/MySqlStatementParser.java#L6506

[joeCarf]

Amend use name at code path below might be the proper way to fix this issue.

https://github.com/polardb/polardbx-sql/blob/ffd596b88044465c0bfdcda7d19a2882fe0acc89/polardbx-parser/src/main/java/com/alibaba/polardbx/druid/sql/dialect/mysql/parser/MySqlStatementParser.java#L6506

when using statement set password for yejr@'%' = password('xx');, variable user is a MySqlUserName object, while using set password for yejr = password('xx'); statement, user is a SQLIdentifierExpr object.

should i just cast SQLIdentifierExpr to MySqlUserName in MysqlStatementParser.class (code path above) or or use if sentense just in code path below ? https://github.com/polardb/polardbx-sql/blob/55ca0c9a51df795e8ad6bed4ce58cdd2d0c70eb3/polardbx-server/src/main/java/com/alibaba/polardbx/server/handler/privileges/polar/PolarSetPasswordHandler.java#L77

[joeCarf]

这个pr还不能合入嘛 @Oldbread3 @ZSYTY