How PHP shows a one-to-many relationship

How does PHP show a one-to-many relationship?
The effects that need to be shown are similar:


One of the clubs may have multiple values.

and the corresponding table structure is as follows:
CREATE TABLE Users (
UID Int (one) is not NULL auto_increment,
uname varchar (32),
PRIMARY KEY (UID)
)

CREATE TABLE groups (
GID Int (one) not NULL auto_increment,
Gname varchar (32),
PRIMARY KEY (GID)
)

CREATE TABLE User_group (
UID Int (11),
GID Int (11)
)

How do you check out and use PHP to show the effect?

------to solve the idea----------------------
Select U.uname, Group_concat (G.gname) from the Users U, user_group ug, Groups G
where U.uid=ug.uid and Ug.gid=g.gid group by U.uid;

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