今天使用Sybase（15.7 Developer版）查询DB时，遇到了很诡异的错误，错误异常如下：
<-- java.sql.SQLException: TDS Protocol error: Invalid packet type 0x22 at net.sourceforge.jtds.jdbc.TdsCore.nextToken(TdsCore.java:2284) at net.sourceforge.jtds.jdbc.TdsCore.isDataInResultSet(TdsCore.java:792) at net.sourceforge.jtds.jdbc.JtdsResultSet.<init>(JtdsResultSet.java:146) at net.sourceforge.jtds.jdbc.JtdsStatement.executeSQLQuery(JtdsStatement.java:424) at net.sourceforge.jtds.jdbc.JtdsPreparedStatement.executeQuery(JtdsPreparedStatement.java:693) at com.trs.infra.persistent.BaseObjs.loadCurrentData(BaseObjs.java:1321) at com.trs.infra.persistent.BaseObjs.open(BaseObjs.java:1437) at com.trs.ekp.stat.obtain.StatResultObtainMgr.queryStatResults(StatResultObtainMgr.java:194) at com.trs.ekp.stat.domain.ExpertLevelMgrTest.testGetAllExpertLevels(ExpertLevelMgrTest.java:51) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at junit.framework.TestCase.runTest(TestCase.java:154) at junit.framework.TestCase.runBare(TestCase.java:127) at junit.framework.TestResult$1.protect(TestResult.java:106) at junit.framework.TestResult.runProtected(TestResult.java:124) at junit.framework.TestResult.run(TestResult.java:109) at junit.framework.TestCase.run(TestCase.java:118) at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:130) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)Caused by: net.sourceforge.jtds.jdbc.ProtocolException: Invalid packet type 0x22 at net.sourceforge.jtds.jdbc.TdsCore.nextToken(TdsCore.java:2271) ... 24 more
经过定位，最终发现是指定的表中的字段个数太多（我这个表中有575个字段），把sql语句修改成select 字段1，字段2 …… from 表
问题不再重现。
select * 时，底层虽然也会提取所有字段，但是会报这个错误，如果我们把所有字段列在select后面，则不会报错，可以正确提取出字段。sql语句变为：select Field1,Field2,Feild3…… from TableName.
后来又测试了下，发现对如果是对decimal字段类型进行排序时，也会报这个错。