MP报错: Mybatis系统异常org.mybatis.spring.MyBatisSystemCannot invoke “net.sf.jsqlparser.statement.Statemen

今天偶然间一个很简单的MP的查询语句报错，百思不得其解：

先看报错：

 - 请求地址'/task/getTaskNumByDemandIdAndStatus', Mybatis系统异常
org.mybatis.spring.MyBatisSystemException: null
	at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:97)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:439)
	at jdk.proxy2/jdk.proxy2.$Proxy184.selectOne(Unknown Source)
	at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:160)
	at com.baomidou.mybatisplus.core.override.MybatisMapperMethod.execute(MybatisMapperMethod.java:87)
	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy$PlainMethodInvoker.invoke(MybatisMapperProxy.java:152)
	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:89)
	at jdk.proxy2/jdk.proxy2.$Proxy193.selectCount(Unknown Source)
	at com.baomidou.mybatisplus.extension.conditions.query.ChainQuery.lambda$count$31c95e6c$1(ChainQuery.java:78)
	at com.baomidou.mybatisplus.extension.conditions.ChainWrapper.execute(ChainWrapper.java:63)
	at com.baomidou.mybatisplus.extension.conditions.query.ChainQuery.count(ChainQuery.java:78)

以及:

Caused by: org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.lang.NullPointerException: Cannot invoke "net.sf.jsqlparser.statement.Statement.toString()" because "statement" is null
### Cause: java.lang.NullPointerException: Cannot invoke "net.sf.jsqlparser.statement.Statement.toString()" because "statement" is null
	at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:156)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:142)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:75)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:425)
	... 98 common frames omitted
Caused by: java.lang.NullPointerException: Cannot invoke "net.sf.jsqlparser.statement.Statement.toString()" because "statement" is null
	at com.baomidou.mybatisplus.extension.parser.JsqlParserSupport.processParser(JsqlParserSupport.java:96)
	at com.baomidou.mybatisplus.extension.parser.JsqlParserSupport.parserSingle(JsqlParserSupport.java:49)
	at com.baomidou.mybatisplus.extension.plugins.inner.TenantLineInnerInterceptor.beforeQuery(TenantLineInnerInterceptor.java:70)
	at com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor.intercept(MybatisPlusInterceptor.java:78)
	at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:59)
	at jdk.proxy2/jdk.proxy2.$Proxy231.query(Unknown Source)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:154)
	... 104 common frames omitted

复现，代码摘要：

原因：
MyBatis Plus.count( ) 和 mapper.xml中的selectCount方法冲突了

解决方案：
改名…即可