On Fri, Sep 12, 2025 at 3:11 PM Dominique Devienne <ddevienne@xxxxxxxxx> wrote: > On Fri, Sep 12, 2025 at 2:45 PM Laurenz Albe <laurenz.albe@xxxxxxxxxxx> wrote: > > You don't show us that data that match the pattern in 17.5, but > > not in 17.6. Unless you show us a counterexample, I'd say that > > the behavior in 17.6 is correct. I've reread https://www.postgresql.org/docs/current/functions-matching.html#FUNCTIONS-SIMILARTO-REGEXP and especially: > According to the SQL standard, omitting ESCAPE means there is no escape character (rather than defaulting to a backslash), and a zero-length ESCAPE value is disallowed. PostgreSQL's behavior in this regard is therefore slightly nonstandard. and also > Another nonstandard extension is that following the escape character with a letter or digit provides access to the escape sequences defined for POSIX regular expressions; see Table 9.20, Table 9.21, and Table 9.22 below. Table 9.21. Regular Expression Class-Shorthand Escapes \d matches any digit, like [[:digit:]] \w matches any word character, like [[:word:]] So I don't see how my `... where v similar to 'foo[\d\w]_%'` is incorrect. So again, is this a bug / regression or not? Thanks, --DD
