how to write mysql trigger

Question

there are two tables
table A

if user use this query \"insert into A values(abc,1,50);\"

then trigger should check student_nam

Answer 1

try like this...

if (Select Count(Name) from B where B.Name=new.name)<1 
insert into summary_score (name,number,all_marks)
values(new.name,new.marks,new.score);
else 
update B set all_marks=old.all_marks+new.student_marks where B.Name=new.Name;

Answer 2

You can simply this by using On Duplicate Key Update . Add a unique key on student name / ID then use the following code in your trigger

begin
   insert into summary_score (name,number,all_marks)
   values(new.name,new.marks,new.score)
   on duplicate key update all_marks=old.all_marks+new.student_marks
  where B.Name=new.Name;
end $$