NULL

功能

控制空列值输出内容。

语法格式

SQL> set NULL 空值输出内容

示例

SQL> select null from dual;

EXPR1 |
------------------------------------------------------------------------------
<NULL> |

Total 1 records.
Use time:0 ms.

SQL> set NULL NULL;
NULL will be display as NULL

SQL> select null from dual;

EXPR1 |
------------------------------------------------------------------------------
NULL |

Total 1 records.
Use time:0 ms.