Question

我是一个完整的SQL菜鸟（之前从未实际使用过），我需要从数据库中删除重复数据，我将在下面发布代码。除了唯一ID之外，重复行完全相同。

public class PostsDatabaseHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "facebookPosts.sqlite";
private static final int VERSION = 2;
private static final String TABLE_POST = "post";

public PostsDatabaseHelper(Context context){
    super(context, DB_NAME, null, VERSION);
}

@Override 
public void onCreate(SQLiteDatabase db){
    db.execSQL("create table post(_id integer primary key autoincrement, filler string, post_id integer,"
            + "application string, caption string, created_time int, description string, from_ string, fromId string,"
            + "link string, message string, name string, picture string, place string, story string, to_ string)");
}

public void deleteDuplicates(){
    getWritableDatabase().rawQuery("DELETE FROM post WHERE post._id NOT IN (SELECT MIN(post._id) FROM post GROUP BY post.post_id", null);
}
}

我已经查看了许多其他主题并尝试了他们的答案，但它仍然无法工作（这可能是对语法的一些误解）。想法？

Answer 1

使用execSQL（String sql）代替rawQuery（String sql，String [] selectionArgs）

public void deleteDuplicates(){
    getWritableDatabase().execSQL("delete from post where _id not in (SELECT MIN(_id ) FROM post GROUP BY post_id)");
}

从SQLite数据库中删除重复项

1 个答案: