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HomeDatabaseMysql TutorialHow to Concatenate Strings in MySQL Using GROUP BY?

How to Concatenate Strings in MySQL Using GROUP BY?

Using GROUP BY connection string in MySQL

In database management systems, it is often necessary to merge multiple strings into a single string. In MySQL, you can use the GROUP BY function to achieve this functionality.

The syntax for MySQL string concatenation is as follows:

SELECT id, GROUP_CONCAT(name SEPARATOR ' ') FROM table GROUP BY id;

This query will group the rows by the id column and concatenate the values ​​in the name column using the specified separator (space in this case).

Example

Consider the following form:

foo_id foo_name
1 A
1 B
2 C

To concatenate the foo_id values ​​for each foo_name you can execute the following query:

SELECT foo_id, GROUP_CONCAT(foo_name SEPARATOR ' ') FROM foo GROUP BY foo_id;

This query will return the following results:

foo_id foo_name
1 A B
2 C

As you can see, each foo_id value of foo_name has been concatenated into a single string.

Additional information

  • GROUP_CONCAT Functions can concatenate any data type, not just strings.
  • You can specify multiple columns in the GROUP BY clause.
  • You can also specify the order in which values ​​are concatenated.

For more information about the GROUP_CONCAT function, see the MySQL documentation: https://www.php.cn/link/18fc3b6cc1e55ccea877c161e2e9ba27

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