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Re: Fixed chars

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Resolved...my missing


Thanks

Enrico


https://www.postgresql.org/docs/10/static/datatype-character.html

"Values of type|character|are physically padded with spaces to the specified width/|n|/, and are stored and displayed that way. However, trailing spaces are treated as semantically insignificant and disregarded when comparing two values of type|character|. In collations where whitespace is significant, this behavior can produce unexpected results; for example|SELECT 'a '::CHAR(2) collate "C" < E'a\n'::CHAR(2)|returns true, even though|C|locale would consider a space to be greater than a newline. Trailing spaces are removed when converting a|character|value to one of the other string types. Note that trailing spaces/are/semantically significant in|character varying|and|text|values, and when using pattern matching, that is|LIKE|and regular expressions."


Il 28/03/2018 11:32, Andreas Kretschmer ha scritto:


Am 28.03.2018 um 11:11 schrieb Enrico Pirozzi:
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)


where is the problem? length() returns the number of chars in string, and the string in codice is 5 chars long.



On the official documentation

|character(/|n|/)|,|char(/|n|/)|     fixed-length, blank padded

https://www.postgresql.org/docs/10/static/datatype-character.html

test=*# select length('12345'::char(10)), pg_column_size('12345'::char(10));
 length | pg_column_size
--------+----------------
      5 |             14
(1 Zeile)



helps that?


Regards, Andreas


--
Enrico Pirozzi
NBS Group S.r.l.
via Val Tiberina 23/A
63074, San Benedetto del Tronto (AP)
Tel. 0735-7626201





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