Sqlite資料庫新增，刪除前n條記錄
阿新 • • 發佈：2019-01-23
1.查詢前N條記錄：
public Cursor query(String sql,String[] selectionArgs){
SQLiteDatabase db=
dbHelper.getReadableDatabase();
return db.rawQuery(sql,selectionArgs);
}
String sql2="SELECT * FROM "+ DetectDao.DETECT_TABLE+" order by "+DetectDao.KEY_ID+" limit 20";
cursor=DetectDao.getInstance(MyService.this).query(sql2, null);
DetectDao.KEY_ID是自增ID。
2.刪除前N條記錄：
public void delete(String sql){
SQLiteDatabase db=dbHelper.getWritableDatabase();
db.execSQL(sql);
}
String sql="DELETE FROM "+ DetectDao.DETECT_TABLE+" where "+DetectDao.KEY_ID+ " in (SELECT "+DetectDao.KEY_ID+" FROM "+ DetectDao.DETECT_TABLE+" order by "+DetectDao.KEY_ID+" limit "+count+")";
DetectDao.getInstance(MyService.this).delete(sql);
DetectDao.KEY_ID是自增ID。