update same uuid in a table where same category id

Question

Hi there,

 

   I have a work to update a pre generated table with uuid.

  Now the problem is i have to update same uuid for same company. for example

 consider a table having the following values .

companyid , value, uuid

1 aa uuid

1 bb uuid

2 cc uuid

3 dd uuid .

 

here now the uuid is null. i have to update it. the problem is for company 1 the uuid should be same. Please help me