How Can I Pivot a MySQL Table with Dynamic Column Names from Row Values?

MySQL dynamic row values ​​as column names

MySQL lacks native pivot functionality for legacy table data that has dynamic row values ​​as column names and is displayed in pivot table format. However, prepared statements using GROUP_CONCAT() can help achieve the desired results.

Sample table:

<code class="language-sql">id    name       value
------------------------------
0     timezone   Europe/London
0     language   en
0     country    45
0     something  x
1     timezone   Europe/Paris
1     language   fr
1     country    46</code>

Target output:

<code>id    timezone       language    country  something
---------------------------------------------------
0     Europe/London  en          45       x
1     Europe/Paris   fr          46</code>

Construct the prepared statement as follows:

<code class="language-sql">SELECT CONCAT(
  'SELECT `table`.id', GROUP_CONCAT('
     ,    `t_', REPLACE(name, '`', '``'), '`.value
         AS `', REPLACE(name, '`', '``'), '`'
     SEPARATOR ''),
 ' FROM `table` ', GROUP_CONCAT('
     LEFT JOIN `table`   AS `t_', REPLACE(name, '`', '``'), '`
            ON `table`.id = `t_', REPLACE(name, '`', '``'), '`.id
           AND `t_', REPLACE(name, '`', '``'), '`.name = ', QUOTE(name)
     SEPARATOR ''),
 ' GROUP BY `table`.id'
) INTO @qry FROM (SELECT DISTINCT name FROM `table`) t;

PREPARE stmt FROM @qry;
EXECUTE stmt;</code>

This query dynamically generates a SELECT statement that uses LEFT JOIN to combine rows with the same id value, extracting the corresponding value for a unique name value. Then press id to group the results to generate the desired pivot table format.

Although MySQL lacks native pivot capabilities, this method provides a way to retrieve data from legacy tables with dynamic column names in a structured manner.

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