[freetds] empty strings select as null bug

Geoff Montee geoff.montee at gmail.com
Wed Jun 10 18:37:59 EDT 2015

On Wed, Jun 10, 2015 at 7:27 AM, Jeffrey Shaw <shawjef3 at gmail.com> wrote:
> I can use PostgreSQL's tds_fdw to use dblib to select from SQL Server. The
> query is
> select id, string is null from distribution.dbo_strings;
> TDS Version = 4.2
> id | ?column?
> ----+----------
>   1 | f
> TDS Version = 7.0
>  id | ?column?
> ----+----------
>   1 | t

As the developer of tds_fdw, I should probably point out to the
FreeTDS developers where my null test code is in case this is a bug on
my end.

tds_fdw assumes a column is NULL if dbdatlen() returns 0:



I implemented it this way because I assumed dbdatlen() should be equal
to 1 for a null terminator character if a string is empty. Let me know
if this is a bad null test.

Could this behavior be related to iconv or character set conversions
in TDS 7.0 and higher?



More information about the FreeTDS mailing list