MySqlJava错误：检查正确的语法，以使用附近的'？'在第1行调用时准备语句[重复]

Question

我正试着打电话给我的数据库，但它总是变得奇怪，我不知道为什么。前一次它能工作，下一次我什么都不做，只是重新启动服务器时，它会出现以下错误：您的SQL语法有错误；查看与您的MySQL服务器版本对应的手册，以了解在“？”附近使用的正确语法在1号线

我已经查看了我在PreparedStatement中提供的id是否为空，是否为空。（这两者都不能是，因为它是一个非空值）在结果集上调用错误（当结果集被执行时）。下面是我用mysql语句尝试的不同方法：

SELECT * FROM registration where `registration_id` > ?
SELECT * FROM registration where registration_id > ?
//what used to work:
SELECT * FROM registration where id > ?

以下是我执行查询的方式：

SQLConnection sqlConnection = new SQLConnection();
            Connection conn = sqlConnection.getConnection();
            String query = "SELECT * FROM registration where `registration_id` > ?";
            try {
                PreparedStatement stmn = conn.prepareStatement(query);
                System.out.println(user.getLastExport());
                stmn.setInt(1, user.getLastExport());
                // execute the query, and get a java resultset
                ResultSet rs = stmn.executeQuery(query);

错误是：

java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 1
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
    at com.mysql.cj.jdbc.StatementImpl.executeQuery(StatementImpl.java:1218)
    at houseoftyping.sql.SQLConnection.fillWorkbookWithLastRegistrations(SQLConnection.java:158)
    at houseoftyping.controller.ExcelController.handleDownload(ExcelController.java:106)
    at houseoftyping.controller.ExcelController.doGet(ExcelController.java:51)
    at houseoftyping.controller.ExcelController.doPost(ExcelController.java:197)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    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:53)
    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:202)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

Answer 1

我知道我做错了什么：

在准备好的声明中，我这样做：

PreparedStatement stmn = conn.prepareStatement(query);

所以这意味着我的查询被加载到准备好的语句中现在我做错了的是我再次将我的查询添加到结果集中，如下所示：

ResultSet rs = stmn.executeQuery(query);

但它需要没有这样的查询：

ResultSet rs = stmn.executeQuery();