PL / SQL遍历所有列并更新

Question

我想更新表格中的每一列，将""替换为"。

以下PL / SQL失败。有没有人有线索？

DECLARE
  COL_NAME  VARCHAR2(400);
  Cursor c1 IS
    SELECT COLUMN_NAME
      FROM USER_TAB_COLS
     WHERE TABLE_NAME = 'COMPANY'
       AND DATA_TYPE = 'VARCHAR2';
BEGIN
  OPEN c1;

  LOOP
   FETCH c1 INTO COL_NAME;
   EXIT WHEN c1%NOTFOUND;

   update COMPANY 
      set COL_NAME = REPLACE (COL_NAME, '""', '"')
    where COL_NAME LIKE '%""%';

  END LOOP;
END;