com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column '' in 'field list'_html/css_WEB-ITnose

严重: Servlet.service() for servlet jsp threw exception
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column '??????' in 'field list'
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.Util.getInstance(Util.java:381)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1030)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2536)
    at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1564)
    at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1485)
    at org.apache.jsp.insert_jsp._jspService(insert_jsp.java:100)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11NioProcessor.process(Http11NioProcessor.java:891)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:750)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:2282)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

 

------解决方案--------------------
这个错很简单
从这代码可以看出 ： String sql="INSERT INTO STUDENT VALUES("+id+","+name+")";
如果 我的 id=1，name=adf 那么组合成的字符串就是
INSERT INTO STUDENT VALUES(1,adf ) 你可以尝试去执行这句SQL，肯定会报错
正确的写法应该是 INSERT INTO STUDENT VALUES(1,'adf' ); --数字类型可以不用加单引号 

所以
应该是 String sql="INSERT INTO STUDENT VALUES("+id+",'"+name+"')";
------解决方案--------------------
遇见这种数据库语句的问题，考虑到语句有字符串的的拼接，你可以用
System.out.print(sql);先将你的语句输出，这样就很容易发现有没有错误。