Re: Zero-length character breaking query?

Doug Gorley <dgorley(at)aihs(dot)ca> writes:
> The table is called tdt_unsent. The field is str_name_l. For demonstration purposes, the value is "SMITH".

> "select * from tdt_unsent where str_name_l = 'SMITH'" returns 0 rows.
> "select * from tdt_unsent where str_name_l ~ '^SMITH'" returns 3 rows.
> "select * from tdt_unsent where str_name_l ~ '^SMITH$'" returns 0 rows.
> "select length(str_name_l) from tdt_unsent where str_name_l ~ '^SMITH'" returns "5".

I'd check EXPLAIN (with the actual problematic string, not SMITH).
The planner is probably trying to build an index range condition from
the regex pattern --- is it doing the right thing given your locale?

If the plan looks okay, maybe you need to reindex whatever index it's
using.

regards, tom lane