一个简单的PL/SQL代码的例子，它做了你解释的事情。它假设表中的所有列都是VARCHAR2，因为你不能把'EMPTY'放入NUMBER或DATE数据类型的列中。如果你在那个表中有不同数据类型的列，在游标的WHERE子句中过滤它们。
样品表：

SQL> CREATE TABLE test
  2  (
  3     col1   VARCHAR2 (10),
  4     col2   VARCHAR2 (10)
  5  );

Table created.

SQL> INSERT INTO test
  2     SELECT 'entry1', NULL FROM DUAL
  3     UNION ALL
  4     SELECT NULL, NULL FROM DUAL
  5     UNION ALL
  6     SELECT 'entry2', 'entry1' FROM DUAL;

3 rows created.

SQL> SELECT * FROM test;

COL1       COL2
---------- ----------
entry1

entry2     entry1

过程使用动态SQL更新NULL值，并使用字符串'EMPTY'：

SQL> DECLARE
  2     l_str  VARCHAR2 (200);
  3  BEGIN
  4     FOR cur_r IN (SELECT column_name
  5                     FROM user_tab_columns
  6                    WHERE table_name = 'TEST')
  7     LOOP
  8        l_str :=
  9              'update test set '
 10           || cur_r.column_name
 11           || q'[ = 'EMPTY' where ]'
 12           || cur_r.column_name
 13           || ' is null';
 14
 15        EXECUTE IMMEDIATE l_str;
 16     END LOOP;
 17  END;
 18  /

PL/SQL procedure successfully completed.

结果：

SQL> SELECT * FROM test;

COL1       COL2
---------- ----------
entry1     EMPTY
EMPTY      EMPTY
entry2     entry1

SQL>

如果要将匿名代码移动到过程中，则：

SQL> rollback;

Rollback complete.

SQL> SELECT * FROM test;

COL1       COL2
---------- ----------
entry1

entry2     entry1

程序：

SQL> CREATE OR REPLACE PROCEDURE p_empty (par_table_name IN VARCHAR2)
  2  IS
  3     l_str  VARCHAR2 (200);
  4  BEGIN
  5     FOR cur_r IN (SELECT column_name
  6                     FROM user_tab_columns
  7                    WHERE table_name = DBMS_ASSERT.sql_object_name (par_table_name))
  8     LOOP
  9        l_str :=
 10              'update '
 11           || par_table_name
 12           || ' set '
 13           || cur_r.column_name
 14           || q'[ = 'EMPTY' where ]'
 15           || cur_r.column_name
 16           || ' is null';
 17
 18  dbms_output.put_line(l_str);
 19        EXECUTE IMMEDIATE l_str;
 20     END LOOP;
 21  END;
 22  /

Procedure created.

测试：

SQL> BEGIN
  2     p_empty ('TEST');
  3  END;
  4  /

PL/SQL procedure successfully completed.

SQL>
SQL> SELECT * FROM test;

COL1       COL2
---------- ----------
entry1     EMPTY
EMPTY      EMPTY
entry2     entry1

SQL>