关于OR关键字的支持

[MLeft]

描述

已经看到Issue#501, 说目前已经支持了OR语句查询, 我使用了最新2.0.3代码, 还是报错

Which version of Sharding-Jdbc do you using?（您使用的Sharding-Jdbc版本为？）

最新 2.0.3

Expected behavior （您预期的结果是）

SQL: select * from PM_SYSPAR where (? is null OR PARCODE = ?) and (? is null OR PARCODE_SUB = ?)
实现对目标库的sql查询

Actual behavior （实际运行的结果是）

Caused by: io.shardingjdbc.core.parsing.parser.exception.SQLParsingUnsupportedException: Not supported token 'OR'.
	at io.shardingjdbc.core.parsing.lexer.LexerEngine.unsupportedIfEqual(LexerEngine.java:178)
	at io.shardingjdbc.core.parsing.parser.clause.WhereClauseParser.parseConditions(WhereClauseParser.java:76)
	at io.shardingjdbc.core.parsing.parser.clause.WhereClauseParser.parse(WhereClauseParser.java:68)

Steps to reproduce the behavior （可重现问题的操作步骤）

Please provide the reproduce example codes (such as github link)，otherwise we will label the issue as Invalid and close it.（为了节省复现问题的时间，请务必提供可重现的代码，否则我们会将issue直接标记为invalid并关闭）

    @Select({
        "select * from PM_SYSPAR",
    	"where ",
        "     (#{parcode,jdbcType=VARCHAR} is null OR PARCODE = #{parcode,jdbcType=VARCHAR})",
        " and (#{parcodeSub,jdbcType=VARCHAR} is null OR PARCODE_SUB = #{parcodeSub,jdbcType=VARCHAR})"
    })
    @Results({
    	@Result(column="PARCODE", property="parcode", jdbcType=JdbcType.VARCHAR, id=true),
        @Result(column="PARNAME", property="parname", jdbcType=JdbcType.VARCHAR),
        @Result(column="PARVALUE", property="parvalue", jdbcType=JdbcType.CLOB),
        @Result(column="PARCLASS", property="parclass", jdbcType=JdbcType.VARCHAR),
        @Result(column="PARSCOPE", property="parscope", jdbcType=JdbcType.VARCHAR),
        @Result(column="PARCODE_SUB", property="parcodeSub", jdbcType=JdbcType.VARCHAR),
        @Result(column="PARCODE_SUB_DESC", property="parcodeSubDesc", jdbcType=JdbcType.VARCHAR)
    })
    List<PmSyspar> checkPmSysparDuplicate(Map<String, Object> map);

Code should based on https://github.com/shardingjdbc/sharding-jdbc-example
（代码请基于 https://github.com/shardingjdbc/sharding-jdbc-example）

[terrymanu]

#501 is still opening. The status of finished features should be closed