Question

Got this:

Table a
ID RelatedBs
1  NULL
2  NULL

Table b
AID ID
1   1
1   2
1   3
2   4
2   5
2   6

Need Table a to have a comma separated list as given in table b. And then table b will become obsolete:

Table a
ID RelatedBs
1  1,2,3
2  4,5,6

This does not rund through all records, but just ad one ‘b’ to ‘table a’

UPDATE a, b
SET relatedbs = CONCAT(relatedbs,',',b.id)
WHERE a.id = b.aid

UPDATE: Thanks, 3 correct answers (marked oldest as answer)! GROUP_CONCAT is the one to use. No need to insert commas between the ids using relatedids = CONCAT(relatedids,’,’,next_id) that is done automatic by GROUP_CONCAT.

Answer 1

You’ll have to use the mysql group_concat function in order to achieve this: http://dev.mysql.com/doc/refman/5.1/en/group-by-functions.html#function_group-concat