Thank you, this works better, but -
the result is correctly "true" now,
but the warning is still there, why?
WARNING: nonstandard use of \\ in a string literal
# select 'axxxxxyz' ~ '(.)\\1\\1';
LINE 1: select 'axxxxxyz' ~ '(.)\\1\\1';HINT: Use the escape string syntax for backslashes, e.g., E'\\'.
^
?column?
----------
t
(1 row)
Because backslash is not normally a valid escape character in an SQL string literal.
You can turn off the warning in your settings, or you can be explicit about wanting a string literal that can include such escape characters by using the E'<string>' notation.
I seem to recall that there's a string literal notation specific to regular expressions as well (R'<regular _expression_>'?), but I may be mixing up databases...
If you can't see the forest for the trees,
Cut the trees and you'll see there is no forest.