On Thu, Jun 15, 2023 at 10:44 AM M Sarwar <sarwarmd02@xxxxxxxxxxx> wrote:
Hello Scott and all,
Here the question comes with respect to CHAR(10) to CHARACTeR VARYING( 10 ) comparison results.char_10 - type character ( 10 )var_char_10 - type character varying ( 10)
When I do the comparison between char_10 and var_char_10 columns, I may get the wrong results.var_char_10 is always trimmed from right.
NO. varchar is never trimmed in this sense. Though casting to a varchar(n) will result in truncation of the input value to n characters - regardless of what those characters are.
char_10 has padded data of blank or spaces.Now I compare char10 and var_char_10 columns, I will get the wrong results because char_10 has padded spaces.
Is that correct or will it ignore whitespaces at the end of char_10 column?
Testing shows that the varchar value gets promoted to char, not the other way around.
postgres=# select '123 '::char(5) = '123 '::varchar;
postgres=# select ('123 '::char(5))::varchar = '123 '::varchar;?column?
No one memorizes char behavior - if you must use it then test your code, and maybe be extra explicit with your casting too.