sql - mysql update a field plus 1 -

hi there want update field plus one.

for example:

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

if code:

update article set likehits = '+1' id ='129'

for result, result 1.

what's wrong?

likehits = '+1' not adds 1 field instead assign literal +1 likehits column value.

in order add 1 try this

update article  set likehits = likehits + 1 id ='129'

however, looks likehits column of type nvarchar, if try (assuming likehits column stores numbers)

update article  set likehits = cast((cast(likehits int) + 1) nvarchar(64))  id ='129'

Ben