string - Oracle 11G 重复 output_put.put_line 两次。如何解决这个问题？

Question

我的循环给了我两倍的结果。因为我只想要一次。我应该怎么办？

 for i in 1..length(newStudentNumber) loop
    character := SUBSTR(newStudentNumber, i, 1);
    newStudentNumber := newStudentNumber || case character
     when 'A' then '16'
     when 'B' then '17'
     when 'C' then '18'
     when 'D' then '19'
     when 'E' then '20'
     when 'F' then '21'
     when 'G' then '22'
     when 'H' then '23'
     when 'I' then '24'
     when 'J' then '25'
     when 'K' then '26'
     when 'L' then '27'
     when 'M' then '28'
     when 'N' then '29'
     when 'O' then '30'
     when 'P' then '31'
     when 'Q' then '32'
     when 'R' then '33'
     when 'S' then '34'
     when 'T' then '35'
     when 'U' then '36'
     when 'V' then '37'
     when 'W' then '38'
     when 'X' then '39'
     when 'Y' then '40'
     when 'Z' then '41'
     else character
    end;
  end loop;
  dbms_output.put_line(newStudentNumber);

我希望我对这个问题不要太含糊

提前致谢

Answer 1

在您的循环中，您将可能转换的字符附加到您正在循环的同一字符串变量中，newStudentNumber. 如果您不想要旧值和新值，那么您需要在循环中填充第二个变量。

  -- new variable, which has to be declared
  convertedStudentNumber := null;
  for i in 1..length(newStudentNumber) loop
    character := SUBSTR(newStudentNumber, i, 1);
    convertedStudentNumber := convertedStudentNumber || case character
    ...
    else character
    end;
  end loop;
  dbms_output.put_line(convertedStudentNumber);

现在这两个变量有不同的值，一个是starting TUE...，另一个是starting 353620...。