null_or_empty

description

Syntax

BOOLEAN NULL_OR_EMPTY (VARCHAR str)

如果字符串为空字符串或者NULL，返回true。否则，返回false。

example

  1. MySQL [(none)]> select null_or_empty(null);
  2. +---------------------+
  3. | null_or_empty(NULL) |
  4. +---------------------+
  5. |                   1 |
  6. +---------------------+
  8. MySQL [(none)]> select null_or_empty("");
  9. +-------------------+
  10. | null_or_empty('') |
  11. +-------------------+
  12. |                 1 |
  13. +-------------------+
  15. MySQL [(none)]> select null_or_empty("a");
  16. +--------------------+
  17. | null_or_empty('a') |
  18. +--------------------+
  19. |                  0 |
  20. +--------------------+

keyword

NULL_OR_EMPTY