MySQL 5.5.15 - Query REGEXP pattern returns weird result

Question

In a text column (HTML) are used placeholders:

[[ID|STRING]]

Examples:

[[2|telefon]]
[[43|name]]

And there are placeholders using the following format:

[[ID|STRING|STRING]]

Examples:

[[56|baustein|s]]

The first string is always named "baustein", the second one is alwys "s" or "d".

I want to get all records where the string column contains the first kind of placeholder but not the second.

My regular expression is:

\[\[#d.id#\|(anrede|name1|name2|name3|strasse|plz|ort|telefon|fax|email|emailaddress|web|bild)\]\]

Notice: #d.id# is a variable containing an integer.

Unfortunately the result of the query includes all records containing the first AND the second placeholder instead of the first one only.

I have tested the regexp using https://regex101.com/ (PCRE2 PHP) and it seems to be ok.

What am I missing in conjunction with MySQL?

Answer 1

Use

REGEXP '[[][[][0-9]+[|](anrede|name1?|name2|name3|strasse|plz|ort|telefon|fax|email|emailaddress|web|bild)]]'

EXPLANATION

--------------------------------------------------------------------------------
  [[]                      any character of: '['
--------------------------------------------------------------------------------
  [[]                      any character of: '['
--------------------------------------------------------------------------------
  [0-9]+                   any character of: '0' to '9' (1 or more
                           times (matching the most amount possible))
--------------------------------------------------------------------------------
  [|]                      any character of: '|'
--------------------------------------------------------------------------------
  (                        group and capture to \1:
--------------------------------------------------------------------------------
    anrede                   'anrede'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    name                     'name'
--------------------------------------------------------------------------------
    1?                       '1' (optional (matching the most amount
                             possible))
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    name2                    'name2'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    name3                    'name3'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    strasse                  'strasse'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    plz                      'plz'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    ort                      'ort'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    telefon                  'telefon'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    fax                      'fax'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    email                    'email'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    emailaddress             'emailaddress'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    web                      'web'
--------------------------------------------------------------------------------
   |                        OR
--------------------------------------------------------------------------------
    bild                     'bild'
--------------------------------------------------------------------------------
  )                        end of \1
--------------------------------------------------------------------------------
  ]]                       ']]'

DO NOT escape ] brackets, escape single characters with character classes, or use doubled backslashes, \\\\[\\\\[ and \\\\| .