mybatis框架XML一些小问题导致错误Caused by: org.xml.sax.SAXParseException: 元素内容必须由格式正确的字符数据或标记组成

背景了解：

mybatis框架下SQL查询一周内数据，由于mybatis对于>=和 <=的不识别，会误认为是括号所有导致了以下错误

报错信息：

 
 
	select IFNULL(SUM(alert_sum),0) as alert_sum from tb_checkresults where
	DATE_SUB(CURDATE(), INTERVAL 7 DAY) <= date(create_time)
 

Caused by: org.apache.ibatis.builder.BuilderException: Error creating document instance.  Cause: org.xml.sax.SAXParseException; lineNumber: 77; columnNumber: 43; 元素内容必须由格式正确的字符数据或标记组成。
	at org.apache.ibatis.parsing.XPathParser.createDocument(XPathParser.java:259)
	at org.apache.ibatis.parsing.XPathParser.(XPathParser.java:125)
	at org.apache.ibatis.builder.xml.XMLMapperBuilder.(XMLMapperBuilder.java:78)
	at org.mybatis.spring.SqlSessionFactoryBean.buildSqlSessionFactory(SqlSessionFactoryBean.java:520)
	... 73 common frames omitted
Caused by: org.xml.sax.SAXParseException: 元素内容必须由格式正确的字符数据或标记组成。
	at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203)
	at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(ErrorHandlerWrapper.java:177)
	at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:400)
	at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:327)
	at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(XMLScanner.java:1438)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.startOfMarkup(XMLDocumentFragmentScannerImpl.java:2637)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2735)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
	at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848)
	at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777)
	at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
	at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:243)
	at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:339)
	at org.apache.ibatis.parsing.XPathParser.createDocument(XPathParser.java:257)
	... 76 common frames omitted

 解决办法：

（1） =和 <=的语句括起来]]>

 
 
	select IFNULL(SUM(alert_sum),0) as alert_sum from tb_checkresults where
	
 

（2）用<；代替小于号，用>；代替大于号

大于: DATE_SUB(CURDATE(), INTERVAL 7 DAY) <= date(create_time)  

                             
小于: DATE_SUB(CURDATE(), INTERVAL 7 DAY) >= date(create_time)

 

找得到，看得懂，明确报错信息很重要

解决问题有多种办法，符合要求的才是最好的