In my collection following query returns some result:
db.c.find({t:/a/})
But below query (and any other regex that has \uXXXX) returns no result:
db.c.find({t:/\u0041/})
What is wrong?
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Handsome Nerd
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Using Ray Toal's answer, Using PCRE \x{XXXX} syntax instead of JavaScript \uXXXX solved problem.
db.c.find({t:/\x{0041}/})
Handsome Nerd
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1Wow, this answer from nearly 7 years ago still works. Nice one. – Reece Daniels May 20 '19 at 12:15
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The reason for this is that according to the documentation
MongoDB uses PCRE for regular expressions.
However the PCRE documentation says
The following Perl escape sequences are not supported: \l, \u, \L, \U, and \N when followed by a character name or Unicode value. (\N on its own, matching a non-newline character, is supported.) In fact these are implemented by Perl's general string-handling and are not part of its pattern matching engine. If any of these are encountered by PCRE, an error is generated by default. However, if the PCRE_JAVASCRIPT_COMPAT option is set, \U and \u are interpreted as JavaScript interprets them.
That said, this SO question may be of some help.
