Hi , I've seen this strange thing. sitedb=# create table test_tb(codice char(7)); CREATE TABLE sitedb=# insert into test_tb values('pippo'); INSERT 0 1 sitedb=# select codice || 'a'::char(1),length(codice) from test_tb ?column? | length ----------+-------- pippoa | 5 (1 row) On the official documentation |character(/|n|/)|,|char(/|n|/)| fixed-length, blank padded https://www.postgresql.org/docs/10/static/datatype-character.html Can anyone help me? Enrico -- Enrico Pirozzi NBS Group S.r.l. via Val Tiberina 23/A 63074, San Benedetto del Tronto (AP) Tel. 0735-7626201