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Java 如何传递特定字符串以从数据库中获取特定值_Java_Android_Database_Sqlite_Android Sqlite - Fatal编程技术网

Java 如何传递特定字符串以从数据库中获取特定值

Java 如何传递特定字符串以从数据库中获取特定值,java,android,database,sqlite,android-sqlite,Java,Android,Database,Sqlite,Android Sqlite,我有三列,其中拖车编号和拖车id是字符串 id trailer_number trailder_id 1 trailer1 766 2 trailer2 899 3 trailer3 577 现在,如果我传递了拖车号,如何获得特定的拖车id。 比如说:trailer1如果我通过了,如何返回字符串“766” 我只能在特定字符串存在或不存在的情况下进行操作,但我不知道如何传递以获取特定id public boolean

我有三列,其中拖车编号和拖车id是字符串

id   trailer_number  trailder_id
1       trailer1       766
2       trailer2       899
3       trailer3       577
现在,如果我传递了拖车号,如何获得特定的拖车id。 比如说:trailer1如果我通过了,如何返回字符串“766”

我只能在特定字符串存在或不存在的情况下进行操作,但我不知道如何传递以获取特定id

public boolean isExist(String strTrailerNumber) {
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cur = db.rawQuery("SELECT * FROM " + TABLE_NAME + " WHERE TRAILER_NUMBER = '" + strTrailerNumber + "'", null);
        boolean exist = (cur.getCount() > 0);
        cur.close();
        db.close();
        return exist;

    }
试用期如下:

 String query = "SELECT trailder_id FROM TABLE_NAME WHERE TRAILER_NUMBER =" + strTrailerNumber ;
        Cursor  cursor = database.rawQuery(query,null);
        if (cursor.moveToFirst()) {
                 while (cursor.isAfterLast() != true) {
                   string trailder_id =  cursor.getString(cursor.getColumnIndex("trailder_id")));
                  }
        }
查询中可能有语法错误,请更改它。它会起作用。

使用查询

"SELECT trailder_id FROM " + TABLE_NAME + " WHERE TRAILER_NUMBER = '" + strTrailerNumber + "'"
和使用

cursor.moveToFirst()
String trailer_id = cursor.getString(0)
要获取trailder_id

“请从“+表名+”中选择trailder_id,其中trailder_编号=”“+strTrailerNumber+”,null)