sql - mysql what is the right syntax for this conditional update statement -

mysql, want like

update tablename   case fielda  when value1 set fieldx0=xxx,fieldx1=bbb,fieldx2=ccc ...  when value2 set fieldy0=yyy,fieldy1=eee,fieldy2=fff ...  end 

what right , simple syntax it? thank much.

it should written way:

update tablename set fieldx = case when fielda = 'value1' 'xxx' else fieldx end,     fieldy = case when fielda = 'value2' 'yyy' else fieldy end fielda in ('value1', 'value2');  

note that: wrote else part way, because default else null if condition of case expression not valid, set original value not null value.