一、drop已经存在的外键报错

• io.debezium.text.ParsingException: DDL statement couldn’t be parsed.
• no viable alternative at input ‘ALTER TABLE mytable DROP FOREIGN KEY IF’ at io.debezium.antlr.ParsingErrorListener.syntaxError(ParsingErrorListener.java:43)
  at org.antlr.v4.runtime.ProxyErrorListener.syntaxError(ProxyErrorListener.java:41)

二、修改源码MySqlParser.g4

debezium-ddl-parser/src/main/antlr4/io/debezium/ddl/parser/mysql/generated/MySqlParser.g4

    | DROP FOREIGN KEY uid ifExists?