How to Dynamically Concatenate All Columns in MySQL

Concatenating Columns in MySQL: Dive into Dynamic Approaches

Concatenating all columns in a MySQL table using the * keyword is not feasible. To accomplish this, you must explicitly list each column. However, this process can become tedious if you have numerous columns. Let's explore alternative methods to access column values dynamically.

Concatenating Columns Manually

To concatenate specific columns, you can use the CONCAT function. Simply specify the desired columns, as seen below:

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

Using CONCAT_WS for Efficient Concatenation

To prevent null values from interfering, consider using CONCAT_WS:

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

Dynamically Generating Column Names

If manually specifying column names is impractical, you can leverage dynamic queries to retrieve all column names in your table.

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

This query generates a list of column names, which you can concatenate using GROUP_CONCAT.

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

Combining Elements for a Dynamic Query

Now that you have all the necessary components, let's construct a dynamic query:

SELECT
  CONCAT(
    'SELECT CONCAT_WS(\'\',',
    GROUP_CONCAT(CONCAT('`', column_name, '`') ORDER BY column_name),
    ') AS all_columns FROM yourtable;')
FROM   `information_schema`.`columns` 
WHERE  `table_schema`=DATABASE() AND `table_name`='yourtable'
INTO @sql;

This query sets the @sql variable to the desired concatenation query.

PREPARE stmt FROM @sql;
EXECUTE stmt;

By executing this code, you can dynamically concatenate all columns in your table. Refer to the provided fiddle for a working example.

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