MySQL REPLACE:Jak nahradit všechny výskyty znaku v každém samostatném podřetězci odděleném stejnou hlavou a koncem

je to možné pouze v čisté MySQL bez použití plnohodnotného HTML parseru nebo UDF, které by importovaly funkci REGEX_REPLACE do MySQL.

Trik spočívá v použití generátoru čísel a použití vnořeného SUBSTRING_INDEX k rozdělení velkého řetězce na html tagy
Tento generátor čísel vygeneruje číslo od 1 do 10 000
Takže „analyzátor“ bude podporovat až 10 000 štítků, pokud potřebujete více, musíte přidat další

CROSS JOIN (
     SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
    ) AS record_[number]

Dotaz

SELECT 
 (@number := @number + 1) AS number
FROM (    
  SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
) AS record_1
CROSS JOIN (
  SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
) AS record_2
CROSS JOIN (
 SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
) AS record_3
CROSS JOIN (
  SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
) AS record_4
CROSS JOIN ( SELECT @number := 0 ) AS init_user_param

tento příkaz SQL bude použit k rozdělení na html tag

Příkaz SQL

CONCAT(SUBSTRING_INDEX(SUBSTRING_INDEX([large_html_string], ">", [tag_position]), ">", -1), ">") as tag 

Trik nyní spočívá v kombinaci generátoru čísel a rozdělení řetězce html. Takže [tag_position] je vyplněno číslem z generátoru čísel.
To se děje pomocí CROSS JOIN.

Dotaz

SELECT 
 *
FROM ( 

  SELECT 
    CONCAT(SUBSTRING_INDEX(SUBSTRING_INDEX(data, ">", generator.number), ">", -1), ">") as tag 
  FROM (

    SELECT '<p><span><b>C10373 - FIAT GROUP AUTOMOBILES/RAMO DI AZIENDA DI KUEHNE + NAGEL</b></span>
    <p>la somma pari a € 400+IVA per l’attività</p>
    <p>TELE+ A 20.000 LIRE AL MESE </p>
    <li>a mano o via fax al numero +39.00.0.0.0.00.</li>
    <p>Il punteggio base sarà incrementato di un <strong>+ </strong>al ricorrere di ciascuna delle seguenti condizioni:</p>
    <li><a href="/aaa/gare/CIGZB81E5568D+RDO1560277+Obblighi+contattuali-signed.pdf" title="">Obblighi contrattuali</a></li> 
    <li><a href="/aaa/gare/CIGZB81E5568D+RDO1560277+Obblighi+contattuali-signed.pdf" title="">Obblighi contrattuali</a></li> 
    <li><a href="/aaa/gare/CIGZB81E5568D+RDO_1560277Lettera_Invito.pdf" title="">Lettera di invito</a></li>
    <li><a href="/aaa/gare/CIGZB81E5568D+RDO1560277+Obblighi+contattuali-signed.pdf" title="">Obblighi contrattuali</a></li> 
    <li><a href="/aaa/gare/CIGZB81E5568D+RDO1560277+disciplinare+di+gara-signed.pdf" title="">Disciplinare di gara</a></li>
    <li><a href="/aaa/gare/CIGZB81E5568D+determina+di+aggiudicazione+58+2017.pdf" title="">Determina di aggiudicazione</a></li>' AS data

   ) AS record 
   CROSS JOIN (
     SELECT 
       (@number := @number + 1) AS number
     FROM (    
       SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
     ) AS record_1
     CROSS JOIN (
       SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
     ) AS record_2
     CROSS JOIN (
       SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
     ) AS record_3
     CROSS JOIN (
       SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
     ) AS record_4
     CROSS JOIN ( SELECT @number := 0 ) AS init_user_param
   ) 
    AS generator
 ) 
 AS tags
WHERE 
 tags.tag != '>'

viz ukázka http://www.sqlfiddle.com/#!9/de2ed/32

Nyní máme značky jako samostatné záznamy, které je opravdu snadné nahradit pouze v záznamech, které obsahují "href".

SQL příkaz

 (
    CASE 
      WHEN 
        LOCATE("href", tags.tag) > 0
      THEN 
        REPLACE(tags.tag, "+", " ") 
      ELSE 
        tags.tag
    END
 ) AS tag

viz ukázka http://www.sqlfiddle.com/#!9/de2ed/38

Nyní, když víme, jak nahradit, nyní sloučíme záznamy zpět do jednoho řetězce. K tomu můžeme použít GROUP_CONCAT.

Dotaz

    SET SESSION group_concat_max_len = @@max_allowed_packet;

    SELECT 
     GROUP_CONCAT(
        CASE 
          WHEN 
            LOCATE("href", tags.tag) > 0
          THEN 
            REPLACE(tags.tag, "+", " ") 
          ELSE 
            tags.tag
        END
       SEPARATOR ""
     ) AS html

    FROM ( 

      SELECT 
        CONCAT(SUBSTRING_INDEX(SUBSTRING_INDEX(data, ">", generator.number), ">", -1), ">") as tag 
      FROM (

        SELECT '<p><span><b>C10373 - FIAT GROUP AUTOMOBILES/RAMO DI AZIENDA DI KUEHNE + NAGEL</b></span>
        <p>la somma pari a € 400+IVA per l’attività</p>
        <p>TELE+ A 20.000 LIRE AL MESE </p>
        <li>a mano o via fax al numero +39.00.0.0.0.00.</li>
        <p>Il punteggio base sarà incrementato di un <strong>+ </strong>al ricorrere di ciascuna delle seguenti condizioni:</p>
        <li><a href="/aaa/gare/CIGZB81E5568D+RDO1560277+Obblighi+contattuali-signed.pdf" title="">Obblighi contrattuali</a></li> 
        <li><a href="/aaa/gare/CIGZB81E5568D+RDO1560277+Obblighi+contattuali-signed.pdf" title="">Obblighi contrattuali</a></li> 
        <li><a href="/aaa/gare/CIGZB81E5568D+RDO_1560277Lettera_Invito.pdf" title="">Lettera di invito</a></li>
        <li><a href="/aaa/gare/CIGZB81E5568D+RDO1560277+Obblighi+contattuali-signed.pdf" title="">Obblighi contrattuali</a></li> 
        <li><a href="/aaa/gare/CIGZB81E5568D+RDO1560277+disciplinare+di+gara-signed.pdf" title="">Disciplinare di gara</a></li>
        <li><a href="/aaa/gare/CIGZB81E5568D+determina+di+aggiudicazione+58+2017.pdf" title="">Determina di aggiudicazione</a></li>' AS data

       ) AS record 
       CROSS JOIN (
         SELECT 
           (@number := @number + 1) AS number
         FROM (    
           SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
         ) AS record_1
         CROSS JOIN (
           SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
         ) AS record_2
         CROSS JOIN (
           SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
         ) AS record_3
         CROSS JOIN (
           SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
         ) AS record_4
         CROSS JOIN ( SELECT @number := 0 ) AS init_user_param
       ) 
        AS generator
     ) 
     AS tags
    WHERE 
     tags.tag != '>'

celý dotaz naleznete v ukázce

http://www.sqlfiddle.com/#!9/de2ed/46