Dynamically Concatenating All MySQL Columns

In MySQL, concatenating all columns using the * wildcard is not supported. Instead, you need to explicitly specify each column name in the CONCAT() or GROUP_CONCAT() functions.

Explicit Column Concatenation:

You can use the CONCAT() function to concatenate specific columns:

SELECT CONCAT(col1, col2, col3, ...)
FROM yourtable;

Or, use CONCAT_WS() to concatenate columns with a specified separator, skipping null values:

SELECT CONCAT_WS(',', col1, col2, col3, ...)
FROM yourtable;

Dynamic Column Concatenation:

To avoid manually specifying column names, you can use a dynamic query to retrieve all column names from the information_schema.columns table:

SELECT `column_name`
FROM `information_schema`.`columns`
WHERE `table_schema` = DATABASE()
  AND `table_name` = 'yourtable';

Then, use GROUP_CONCAT() to combine these column names:

GROUP_CONCAT(CONCAT('`', column_name, '`'))

This will result in a comma-separated list of quoted column names, such as:

`col1`,`col2`,`col3`,`col4`,...

With this, you can create a dynamic query to concatenate all columns:

SET @sql = CONCAT(
  'SELECT CONCAT_WS(\'\',',
  GROUP_CONCAT(CONCAT('`', column_name, '`') ORDER BY column_name),
  ') AS all_columns FROM yourtable;'
);

Finally, execute the dynamic query:

PREPARE stmt FROM @sql;
EXECUTE stmt;