mysql update a field plus 1

Question

hi there I want update a field plus one.

for example:

if 0 -> 0+1
if 1 -> 1+1

if do it with this code:

UPDATE article SET likehits = '+1' WHERE id ='129'

for all result, the result is 1.

what's the wrong?

Answer 1

likehits = '+1' will not actually add one to a field instead it will just assign literal +1 to likehits column value.

In order to add 1 try this

UPDATE article 
SET likehits = likehits + 1
WHERE id ='129'

However, it looks like likehits column is of type nvarchar, if so then try this (assuming likehits column stores only numbers)

UPDATE article 
SET likehits = CAST((CAST(likehits AS INT) + 1) AS nvarchar(64)) 
WHERE id ='129'