Question

I want to join table Documents(id, name) and Tags(tagId, tagname, docId(FK)). However result will return many redundant rows because one document can has many tags:

Document_name |Tag
----------------------
document01     tag01
document01     tag02
document02     tag01

All I try to resolve is:

document_name |Tags
----------------------------
document01    | tag01, tag02
document02    | tag01

or can be like this:

Document_name |Tag_1   |Tag_2  |Tag_...
---------------------------------------
document01     tag01  |tag02
document02     tag01

Anyone know how can implement this case? Thanks a lot! (I’m trying to find other answer in this site, but I don’t know suitable keyword to search in this case)

Answer 1

if you are using MySQL you can do this:

select document_name, group_concat(tag SEPARATOR ', ')
from Documents
group by document_name