Java Android数据库错误：没有此类列错误

这是logcat

11-14 11:38:28.915  30243-30243/com.example.multical E/SQLiteLog﹕ (1) **no such column: isu**
11-14 11:38:28.925  30243-30243/com.example.multical E/AndroidRuntime﹕ **FATAL EXCEPTION: main**
Process: com.example.multical, PID: 30243
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.multical/com.example.multical.grade}: **android.database.sqlite.SQLiteException: no such column: isu (code 1): , while compiling: SELECT _id, subject, semester, credit, grade, isu FROM mygrades ORDER BY _id DESC**

Caused by: android.database.sqlite.SQLiteException: no such column: isu (code 1): , while compiling: SELECT _id, subject, semester, credit, grade, isu FROM mygrades ORDER BY _id DESC
                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)

**at com.example.multical.DBAdapter.getAllInfo(DBAdapter.java:88)
        at com.example.multical.grade.onCreate(grade.java:81)**

com.example.multical.DBAdapter.getAllInfo(DBAdapter.java:88) source

Cursor c = db.query(TABLE_NAME, new String[]{ID, SUBJECT, SEMESTER, CREDIT, GRADE, ISU}, null, null, null,null, ID + " DESC");

com.example.multical.grade.onCreate(grade.java:81)**

    mInfo = mDb.getAllInfo();

和适应虚荣的人

private static final String DB_NAME = "mygrade.db";
private static final int VERSION = 1;
public static Cursor cursor;
private static final String ID = "_id";
private static final String SUBJECT = "subject";
private static final String SEMESTER = "semester";
private static final String GRADE = "grade";
private static final String ISU = "isu";
private static final String CREDIT = "credit";
private static final String TABLE_NAME = "mygrades";
public static int count;
private static final String CREATE_TABLE =
    "CREATE TABLE " + TABLE_NAME + " (" +
    ID + " integer primary key autoincrement, " +
            SUBJECT + " text not null, " +
            SEMESTER + " text not null," + CREDIT +" text not null, " + GRADE +" text not null, " + ISU + " text not null );";

也许，我认为

Cursor c=db.query（TABLE_NAME，new String[]{ID，SUBJECT，sement，CREDIT，GRADE，ISU}，null，null，null，null，ID+“DESC”）发生了。
那是怎么回事？？？
请帮助我，我将不胜感激。TT
首先卸载应用程序，然后重新安装应用程序。也可以将数据库版本1更改为2。这可能会对您有所帮助。
@Johnmin如果您更改表结构，而数据库中的旧表不变，则这是可能的。要更改它，您必须增加DB版本，或者必须清除旧数据哦！！非常感谢。由于更改了数据库版本2，此应用程序运行良好。非常感谢你