Android-检查数据库中是否存在一行

Question

I've created a method where the app checks if a number exists in the DB:

    Cursor player = playerDatabase.rawQuery("select * from playerTable where playerNumber ="+number,null);
  try {
      if (player.getCount() >= 0) {
          player.close();
          return true;
      }
      else{
          return false;
      }
  }finally {
      if(player != null){
          player.close();
      }
  }

But the problem is, this always returns true? The reason I am using it this way, is from the previous answers on Stack Overflow. What is the optimal way of being able to check if a search query returns a row/check if this number exits?

Answer 1

This is the most efficient way to find if a row exists or not.

SELECT EXISTS(SELECT 1 FROM playerTable WHERE playerNumber="Here comes the player number");

It will return 1 if there is a row with playerNumber in the table or will return 0 if there is no row in the table.