It looks like you are performing an insert within your trigger on the table the trigger is running from
CREATE trigger In_LoaiDG1 on KhaoSat_LoaiDG1
insert into KhaoSat_LoaiDG1
Any clues as to why this may be a bad idea? Hint - infinity... Just remove:
else
insert into KhaoSat_LoaiDG1(MaLoaiTT,Muc1,NgayDG) values (@MaLoaiTT,1,@NgayDG)
and see what happens.
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens