support parsing SHOW RELAYLOG EVENTS for mysql

[tuichenchuxin]

Hi community,

This issue can be a good first try.

Aim

support parse mysql administration statements sql SHOW RELAYLOG EVENTS

Basic Qualifications

• java
• maven
• antlr4

Detail

We have completed the clone rule in DALStatement.g4.
But have not yet implement the visit method in shardingsphere-sql-parser/shardingsphere-sql-parser-dialect/shardingsphere-sql-parser-mysql/src/main/java/org/apache/shardingsphere/sql/parser/mysql/visitor/statement/impl/MySQLDALStatementSQLVisitor.java
To complete this issue, I think we should complete these steps:

• Create MySQLShowRelaylogEventsStatement class in this package org.apache.shardingsphere.sql.parser.sql.dialect.statement.mysql.dal
• Add rule in shardingsphere-sql-parser/shardingsphere-sql-parser-engine/src/main/java/org/apache/shardingsphere/sql/parser/core/database/visitor/SQLVisitorRule.java
• Implement the visit method in shardingsphere-sql-parser/shardingsphere-sql-parser-dialect/shardingsphere-sql-parser-mysql/src/main/java/org/apache/shardingsphere/sql/parser/mysql/visitor/statement/impl/MySQLDALStatementSQLVisitor.java.
• Finally, add test for parse clone statement in shardingsphere-test module

Example FYI

• Refer to this merged pr：https://github.com/apache/shardingsphere/pull/12979/files