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Re: Substring expression fails on single character input - Mailing list pgsql-bugs

From Tom Lane
Subject Re: Substring expression fails on single character input
Date
Msg-id 18207.1589292628@sss.pgh.pa.us
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In response to Substring expression fails on single character input  (Per-Åke Ling <perake.ling@gmail.com>)
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=?UTF-8?Q?Per=2D=C3=85ke_Ling?= <perake.ling@gmail.com> writes:
> When using the expression *'(\S.*\S)' *to remove surrounding whitespace
> (including \t and \n) it returns NULL on single character surrounded by
> whitespace.

I see no bug there.  The pattern requires two non-white-space characters
surrounding some arbitrary text, and your examples don't have that.

If your goal is to trim leading/trailing whitespace I'd suggest that btrim
is a lot easier route to the goal than coming up with a correct regex.

            regards, tom lane

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