PostgreSQL - empty values that are not null and not empty strings

Question

I ran this query on a PostgreSQL table:

select * wkt from table  where column <>'' and  column is not null

..and unexpectedly received several rows with no visible value in that column. Why is this? Is there some 'hidden' value in that column for those rows, or a corrupted table, or something else?

i belive many value will be invisible, eg ascii 0,1,2,3,4,5,6,7, depends on client though — Vao Tsun
– Vao Tsun, Commented Jan 25, 2018 at 16:30

Vao Tsun · Accepted Answer · 2018-01-25 16:34:50Z

5

t=# select ascii(chr(9));
 ascii
-------
     9
(1 row)

thus

select ascii(column) from table  where column <>'' and  column is not null

should give the idea

https://www.postgresql.org/docs/current/static/functions-string.html

ASCII code of the first character of the argument. For UTF8 returns the Unicode code point of the character. For other multibyte encodings, the argument must be an ASCII character.

answered Jan 25, 2018 at 16:34

Vao Tsun

52.4k13 gold badges114 silver badges149 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

PostgreSQL - empty values that are not null and not empty strings

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related