why it has two join?

[jiatongwu]

QueryExpressionDSL<SelectModel>.JoinSpecificationFinisher on = SqlBuilder
							.select(StudentDynamicSqlSupport.id, StudentDynamicSqlSupport.name,
									StudentDynamicSqlSupport.idcard)
							.from(StudentDynamicSqlSupport.student).join(StudentRegDynamicSqlSupport.studentReg)
							.on(StudentDynamicSqlSupport.id, SqlBuilder.equalTo(StudentRegDynamicSqlSupport.studentid));
					// build()
					// render(RenderingStrategy.MYBATIS3)
					if ((byIdcard) && (byRegCode) && (byExamcode)) {
						if (StringUtils.isBlank(examcodeCellString) || StringUtils.isBlank(regCodeCellString)
								|| StringUtils.isBlank(idcardCellString)) {
							errorMsgStringBuilder.append(" 准考证号不能为空 报名号不能为空 身份证号不能为空 ");
							isDataFormatOk = false;
						} else {
							on.where(StudentDynamicSqlSupport.idcard, SqlBuilder.isEqualTo(idcardCellString))
									.and(StudentRegDynamicSqlSupport.examnumber,
											SqlBuilder.isEqualTo(examcodeCellString))
									.and(StudentRegDynamicSqlSupport.regcode, SqlBuilder.isEqualTo(regCodeCellString));
						}
					} else if ((!byIdcard) && (byRegCode) && (byExamcode)) {
						if (StringUtils.isBlank(examcodeCellString) || StringUtils.isBlank(regCodeCellString)) {
							errorMsgStringBuilder.append(" 准考证号不能为空 报名号不能为空  ");
							isDataFormatOk = false;
						} else {
							on.where(StudentRegDynamicSqlSupport.examnumber, SqlBuilder.isEqualTo(examcodeCellString))
									.and(StudentRegDynamicSqlSupport.regcode, SqlBuilder.isEqualTo(regCodeCellString));
						}
					} else if ((byIdcard) && (!byRegCode) && (byExamcode)) {
						if (StringUtils.isBlank(examcodeCellString) || StringUtils.isBlank(idcardCellString)) {
							errorMsgStringBuilder.append(" 准考证号不能为空 身份证号不能为空 ");
							isDataFormatOk = false;
						} else {
							on.where(StudentDynamicSqlSupport.idcard, SqlBuilder.isEqualTo(idcardCellString)).and(
									StudentRegDynamicSqlSupport.examnumber, SqlBuilder.isEqualTo(examcodeCellString));
						}
					} else if ((byIdcard) && (byRegCode) && (!byExamcode)) {
						if (StringUtils.isBlank(idcardCellString) || StringUtils.isBlank(regCodeCellString)) {
							errorMsgStringBuilder.append("  报名号不能为空 身份证号不能为空 ");
							isDataFormatOk = false;
						} else {
							on.where(StudentDynamicSqlSupport.idcard, SqlBuilder.isEqualTo(idcardCellString))
									.and(StudentRegDynamicSqlSupport.regcode, SqlBuilder.isEqualTo(regCodeCellString));
						}
					} else if ((!byIdcard) && (!byRegCode) && (byExamcode)) {
						if (StringUtils.isBlank(examcodeCellString)) {
							errorMsgStringBuilder.append(" 准考证号不能为空  ");
							isDataFormatOk = false;
						} else {
							on.where(StudentRegDynamicSqlSupport.examnumber, SqlBuilder.isEqualTo(examcodeCellString));
						}
					} else if ((byIdcard) && (!byRegCode) && (!byExamcode)) {
						if (StringUtils.isBlank(idcardCellString)) {
							errorMsgStringBuilder.append("  身份证号不能为空 ");
							isDataFormatOk = false;
						} else {
							on.where(StudentDynamicSqlSupport.idcard, SqlBuilder.isEqualTo(idcardCellString));
						}
					} else if ((!byIdcard) && (byRegCode) && (!byExamcode)) {
						if (StringUtils.isBlank(regCodeCellString)) {
							errorMsgStringBuilder.append(" 报名号不能为空  ");
							isDataFormatOk = false;
						} else {
							on.where(StudentRegDynamicSqlSupport.regcode, SqlBuilder.isEqualTo(regCodeCellString));
						}
					}
					if (isDataFormatOk) {
						SelectStatementProvider selectStatementProvider = on.build().render(RenderingStrategy.MYBATIS3);
						List<Student> students = studentDynamicSqlMapper.selectMany(selectStatementProvider);
						if (students.size() == 1) {
							studentId = students.get(0).getId();
							student = students.get(0);
						} else {
							errorMsgStringBuilder.append(" 此考生不存在  ");
							isDataFormatOk = false;
						}
					}

2019-06-27 14:45:01.513 DEBUG 19673 --- [io-18080-exec-1] c.x.m.S.selectMany : ==> Preparing: select student.id, student.name, student.idcard from student join student_reg on student.id = student_reg.studentId join student_reg on student.id = student_reg.studentId
2019-06-27 14:45:01.520 DEBUG 19673 --- [io-18080-exec-1] c.x.m.S.selectMany : ==> Parameters:
2019-06-27 14:45:01.818 INFO 19673 --- [io-18080-exec-1] o.s.b.f.xml.XmlBeanDefinitionReader : Loading XML bean definitions from class path resource [org/springframework/jdbc/support/sql-error-codes.xml]
org.springframework.jdbc.BadSqlGrammarException:

Error querying database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Not unique table/alias: 'student_reg'

The error may exist in cn/xvkang/mapperdynamicsql/StudentDynamicSqlMapper.java (best guess)

The error may involve cn.xvkang.mapperdynamicsql.StudentDynamicSqlMapper.selectMany-Inline

The error occurred while setting parameters

SQL: select student.id, student.name, student.idcard from student join student_reg on student.id = student_reg.studentId join student_reg on student.id = student_reg.studentId

Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Not unique table/alias: 'student_reg'

; bad SQL grammar []; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Not unique table/alias: 'student_reg'
at org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:91)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:73)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:82)
at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:446)
at com.sun.proxy.$Proxy85.selectList(Unknown Source)
at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:230)
at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:139)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:76)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)
at com.sun.proxy.$Proxy97.selectMany(Unknown Source)
at cn.xvkang.service.impl.ExcelAutoLuquServiceImpl.excelAutoLuqu(ExcelAutoLuquServiceImpl.java:211)
at cn.xvkang.controller.ExcelAutoLuquController.excelAutoLuqu(ExcelAutoLuquController.java:28)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:854)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:765)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at cn.xvkang.securiy.ImageValidateCodeFilter.doFilterInternal(ImageValidateCodeFilter.java:38)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:66)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:347)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:263)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:798)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:808)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Not unique table/alias: 'student_reg'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.Util.getInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:944)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3978)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3914)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2530)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2683)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2495)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1903)
at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1242)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.tomcat.jdbc.pool.StatementFacade$StatementProxy.invoke(StatementFacade.java:114)
at com.sun.proxy.$Proxy119.execute(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.ibatis.logging.jdbc.PreparedStatementLogger.invoke(PreparedStatementLogger.java:59)
at com.sun.proxy.$Proxy120.execute(Unknown Source)
at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:63)
at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79)
at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:63)
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:326)
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
at com.github.pagehelper.PageInterceptor.intercept(PageInterceptor.java:108)
at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)
at com.sun.proxy.$Proxy116.query(Unknown Source)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433)

[jeffgbutler]

I've recreated this and there is definitely something to fix here - the query should only have one join specification for sure.

You can resolve it now.... the calls to on.where(...) return an object of type QueryExpressionDSL<SelectModel>.QueryExpressionWhereBuilder. If you call the build() method on that object, you will get the correct output.

Your logic here is pretty complex - you will also need to make sure that you don't call the where method more than once or you might get other strange results.

[jeffgbutler]

Resolved via #106

[jeffgbutler]

@jiatongwu a fix for this is released and available now in version 1.1.2

This page has an example of how I think the new version could make your code a bit cleaner: http://www.mybatis.org/mybatis-dynamic-sql/docs/complexQueries.html