GROUP_CONCAT in MySQL
GROUP_CONCAT(expr) – This function returns a string result with the concatenated non-NULL values from a group.
Where it can be useful?
For example to get PHP array without looping inside PHP:
CREATE TABLE services (
id INT UNSIGNED NOT NULL,
client_id INT UNSIGNED NOT NULL,
KEY (id));
INSERT INTO services
VALUES (1,1),(1,2),(3,5),(3,6),(3,7);
SELECT id,client_id FROM services WHERE id = 3;
+----+-----------+
| id | client_id
+----+-----------+
| 3 | 5
| 3 | 6
| 3 | 7
+----+-----------+
SELECT id,GROUP_CONCAT(client_id) FROM services WHERE id = 3 GROUP BY id;
+----+-------------------------+
| id | GROUP_CONCAT(client_id)
+----+-------------------------+
| 3 | 5,6,7
+----+-------------------------+
Read more: MySQL Performance Blog » GROUP_CONCAT useful GROUP BY extension
This is really a very useful function in Business Logic !!
Thank You…
what if I want to separate them with something different than just ” , ” (comma).
thanks in advance..
You can define your separator -
GROUP_CONCAT(client_id SEPARATOR ‘:’)
Check the GROUP_CONCAT definition over at:
http://gourl.in/2d
This is very interesting function
This is very interesting function
SELECT GROUP_CONCAT(userId SEPARATOR ':') FROM …..
Outstanding function, Thank you Very Much. Great………