How to use GROUP BY to concatenate strings in MySQL?

Question

Basically the question is how to get from this:

id    string
1          A
1          B
2          C

to this:

id    string
1          A B
2          C

Answer 1

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

http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat

Answer 2

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

More details here.

Answer 3

SELECT id, GROUP_CONCAT(CAST(string as CHAR)) FROM table GROUP BY id

Will give you a comma-delimited string

Answer 4

GROUP_CONCAT has max data size limit 1024 and can be increased upto 67107840.How can we resolve this when large data retrieval is required.Can any on reply soon

Answer 5

SET group_concat_max_len=100000000