How to concatenate text from multiple rows into a single text string in MySQL?

Problem

You need to concatenate text from multiple rows into a single text string, for every group present in another column using SQL.

For example, from the employee_comments table, concatenate all comments from a given employee in one row. See the input and the desired output below.

Input

employee_id	comment_text
1	John is a hard worker.
1	John is very reliable.
2	Alice is a great team player.
3	Bob always meets deadlines.

Try Hands-On: Fiddle

Create Input Table: Gist

Desired Output

employee_id	concatenated_comments
1	John is a hard worker. John is very reliable.
2	Alice is a great team player.
3	Bob always meets deadlines.

There are multiple ways to do this. Let’s look at some of them.

Solution:

Using GROUP_CONCAT() with GROUP BY

    SELECT
        employee_id,
        GROUP_CONCAT(comment_text SEPARATOR ' ') AS concatenated_comments
    FROM
        employee_comments
    GROUP BY
        employee_id;

Explanation:

This query selects the employee_id and concatenates the comment_text for each employee with a space separator. The GROUP BY clause groups the results by employee_id.

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