>

>select * from student where scode=zscode and lcode=zlcode and sec=zsec and admtd=1
>into cursor curToProcess nofilter
>select * from curToProcess left join ExamTran ex on ... where ex.code is NULL into cursor curToInsert nofilter
>
>insert into ExamTran (code) select code from curToInsert
>update examtran
>set (all your changes)
>from curToProcess inner join ExamTran on curToProcess.code = ExamTran.code
>

>
>From the top of my head and not tested.

Perhaps this can be simplified a bit more. First do update, then insert with updates implied for the codes not found.

Also there is a trick if code is a PK:

try
  insert .... (with changes)
catch
  update with changes
endtry