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:
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
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:
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;
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.
The above is the detailed content of How Can I Pivot a MySQL Table with Dynamic Column Names from Row Values?. For more information, please follow other related articles on the PHP Chinese website!

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