I have a problem with a trigger insert - update...

I need a trigger for each row that is insert into a table1 and search into a table2 a data with a data in a table1 and update this row... someone can help??

For example:

Number Serie Mtx
21 23 A
532 78 B

Ini Fin Mtx
100 300 A
400 600 B

After a row is insert in table1, I need to search in table2 the MTX is the number is between ini and fin of table2 and update table1....

But I can´t!!

Please Help!!!!