如何将两列的值作为值添加到SQL中的另一列

Question

我有一张这样的表：

S.No | (C1) |  (C2)  | (C3) | (C1+C2+C3)
-----------------------------------------------
1    |  2   |   4    |  5   | (I want 11 here)
-----------------------------------------------
2    |  5   |   2    |  0   | (I want 7 here)
-----------------------------------------------

如何为此编写SQL查询？

任何人请帮助我。

提前致谢。

Answer 1

试试这句话。

select ROW_NUMBER() OVER(ORDER BY c1 DESC) AS SerialRowNum, c1,c2,c3, (c1 + c2 c3) as Total from table

Answer 2

posudo看起来像：

private  class get_txt_from_url extends AsyncTask<String , Void , String>{
        final String TAG = "get_txt_from_url";


        @Override
        protected String doInBackground(String... params) {

            InputStream is = null;
            BufferedReader reader = null;
            StringBuilder string_builder = null;
            String line ="";


            try {
                HttpClient hc = new DefaultHttpClient();
                HttpPost hp = new HttpPost(params[0]);
                HttpResponse hr = hc.execute(hp);
                HttpEntity htity = hr.getEntity();
                is = htity.getContent();
            } catch (IOException e) {
               Log.d(TAG , "ZERO");
            }

            try {
                reader = new BufferedReader(new InputStreamReader(is , "utf-8") , 8);
                string_builder = new StringBuilder();
            } catch (UnsupportedEncodingException e) {
                Log.d(TAG, "ONE");
            }


            try {
                while((line = reader.readLine()) != null){
                    string_builder.append(line+"");
                }
            } catch (IOException e) {
                Log.d(TAG, "line");
            }


            return string_builder.toString();
        }

        @Override
        protected void onPostExecute(String s) {

            Log.d(TAG , s);

        }
    }

Answer 3

如果要在列值中使用它，请使用下表中的VIRTUAL列。

Create table your_table_name
(C1 number,
C2 number,
C3 number,
"C1+C2+C3" NUMBER GENERATED ALWAYS AS (C1+C2+C3) VIRTUAL)

现在，oracle将负责为您生成所需的值。

干杯！