Milan,

>That's because sometimes select returns only one row

gulp

For sure the error is due to the fact that a select returns more than
one row instead of the expected one.

>> select sum(q_c_acq+q_c_div-q_s_ven-q_s_div) from tb_cau1 where
>> cod_cau=bl_lt.cod_cau into :sign;

>this select might return mulitple rows, and then you get the error.

a sum that returns multiple rows ?

Are you kidding ?

Please read carefully my original post then, if you want or can, come
back with a more helpful answer.

Thank you

Duilio Foschi