MySQL空只选中一个列

Question

In mysql I have a table called requests. The table looking like this

 ==================
 |    requests      |
  ==================
  +  id             +
  +  date           +
  +  firstname      +
  +  lastname       +
  +  request_number +
  +  status         +
  +++++++++++++++++++

Now here I want that on single button click I will delete all the values stored inside request_number and the request_number column will be only empty.It will not delete the column name

Answer 1

If you need to empty request_number cells in entire table

UPDATE requests SET request_number = NULL;

If you need to empty request_number for records having specif condition

UPDATE requests SET request_number = NULL where <your condition>;