Weird behavior with master

[e-gaulue]

SELECT PREG_CAPTURE('/[0-9]*/','AL02814'); => ''
SELECT PREG_CAPTURE('/[0-9]+/','AL02814'); => '02814'
SELECT PREG_CAPTURE('/[0-9]*/','02814AL'); => '02814'
SELECT PREG_CAPTURE('/[0-9]+/','02814AL'); => '02814'

I don't understand the first result. Is there something I forget?

Regards,

[jasny]

PCRE will start with at the beginning of the string, try to match the regex and if it succeeds return the found string. Otherwise it will try the next character

• AL02814 matches? -> return match
• L02814 matches? -> return match
• 02814 matches? -> return match
• 2814 matches? -> return match
• 814 matches? -> return match
• 14 matches? -> return match
• 4 matches? -> return match

With /[0-9]*/ the first case actually matches. (You're looking for 0 or more digits, it has found 0.) So it returns the found match, which is an empty string.

See https://www.regex101.com/r/52ILLZ/1