Tom Lane wrote:
Don Isgitt <djisgitt@xxxxxxxxxxxxxxx> writes:
gds2=# select substring('NE NE SE 2310 FSL 330 FEL' from '^([A-Z][A-Z] )+');
substring
-----------
SE
(1 row)
The pg docs say that this form of substring uses POSIX re's, and my understanding of POSIX re's is they are always greedy. So, why do I get only SE instead of NE NE SE? Pilot error, probably, but would someone please enlighten me? Thank you very much.
I think you want
regression=# select substring('NE NE SE 2310 FSL 330 FEL' from '^(([A-Z][A-Z] )+)'); substring ----------- NE NE SE (1 row)
ie, you need the "+" to be *inside* the capturing parentheses. When it's outside, I guess the engine chooses to consider the last match of the parenthesized subexpression as the thing to return. (I can't recall if this choice is specified in the docs or not.)
regards, tom lane
Thanks, Tom. Interestingly enough, neither my original query or your corrected one returns anything with pg 7.4--another good reason to upgrade to 8.*
Don
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