CODEWITHSUNDEEP
regexpostgresql
wiltomap
wiltomap

Reputation: 4223

PostgreSQL - regex issue

I'm trying the following instruction and I don't understand the TRUE value returned :

SELECT '1' ~ '(0[1-9])|[10-15]' ;

?column?
boolean
----------
t

If I make it simplier again, I still don't understand the value returned :

SELECT '1' ~ '[10-15]' ;

?column?
boolean
----------
t

Thank you for helping !

Thomas

Upvotes: 0

Views: 49

Answers (1)

mu is too short
mu is too short

Reputation: 434665

This regex:

[10-15]

doesn't mean what you think it means. The things inside a character class (i.e. [...]) are individual characters, not strings. So that regex matches a '1', anything between '0' and '1', or a '5'; simplifying, we have [015]. In particular, that regex does not match anything between '10' and '15' as you seem to think.

I think you're looking for:

(0[1-9])|(1[0-5])

You just need to factor out the '1' in the second part of the alternation in the same way that you factored out the '0' in the first part.

Upvotes: 4

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