如何将同一表中的两个值相加并存储在同一表中的计算记录中？

Question

Hi I have one tables here:

equipment
ID,  Owner, Type,    Count  
 1   Bob    phone      10         
 2   Larry  computer   11
 1   Bob    computer   11

What I am trying to do is add the computers that Bob, with id 1, to the computers of Larry's, with id 2. I'm trying to increase the count. The count should be 11+11=22. The new computer count for id 2 should be 22 and should update like this in the database:

equipment
ID,  Owner, Type,    Count  
 1   Bob    phone      10         
 2   Larry  computer   22
 1   Bob    computer   11

If Bob did not have any computer, meaning there was no record with ID = 2, then the record should be created.

Here is my SQL:

INSERT INTO EQUIPMENT(`ID`, `OWNER`, `TYPE`, `COUNT`)
SELECT 1 as t.ID, t.OWNER, t.TYPE, t.COUNT 
FROM EQUIPMENT t 
WHERE t.ID = 2
on duplicate key
update 
   COUNT = COUNT + t.COUNT;

Answer 1

Why are you using insert to update a row?

update equipment e cross join
       (select e1.* from equipment e1 where e1.id = 1) as e1
    select e.count = e.count + e1.count
    where e.id = 2;

Answer 2

Some thing like this

UPDATE Yourtable a
       JOIN Yourtable b
         ON a.NAME = b.NAME
            AND a.ID = b.ID + 1
SET    a.Count = a.Count + b.Count