nested exception is org.apache.ibatis.exceptions.toomanyresultsexception: expected one result (or null) to be returned by selectone(), but found: 3

这个错误消息表明在使用MyBatis的selectOne()方法时，返回了多于一条查询结果，而期望只返回一条或null。可能是因为SQL语句有问题或者参数传递错误导致返回多余的结果。建议检查SQL语句和参数，确保只返回一条结果。

相关问题

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 2] with root cause org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne()

这个错误通常发生在MyBatis查询时返回多个结果，而查询方法应该只返回一个结果或者Null。解决这个问题的方法是检查你的查询语句，确保它只返回一个结果或者在查询语句中添加限制条件，以确保只返回一个结果。你还可以使用MyBatis的selectList()方法来获取多个结果。如果你仍然遇到问题，请提供更多的上下文信息，我会尽力帮你解决问题。

nested exception is org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne()

nested exception is org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 2 是因为在执行sql语句查询时，返回了多条结果，但代码中只期望返回一条结果。这导致了问题的出现。解决这个问题有两种方法可以尝试。

方法一是在Dao层找到对应方法的Sql语句，将该语句复制到数据库中执行。根据注释中所需的字段，传入相应的参数运行Sql语句，查看查询到的数据。如果发现有多余的数据，可以删除这些多余的字段。然后重新发送请求，问题就可以解决了。<span class="em">1</span><span class="em">2</span><span class="em">3</span>
#### 引用[.reference_title]
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