Mysql: Add another column to a table based on matching an id to the second table where there are many matching rows

[surjit singh]

I am learning MySql. I have a table t1
fid
----
ax

kx

Also have a table t2
fid mid
------
ax bx

ax cx

Would like to change table t1 to
fid mid
--------
ax bx, cx

kx NULL

Here is what I tried

ALTER TABLE t1 ADD COLUMN mid text DEFAULT NULL;

update t1

LEFT JOIN t2 ON t1.fid = t2.fid

set t1.mid = t2.mid;

I get
fid mid
--------
ax bx

kx NULL

I would like to have
fid mid
--------
ax bx, cx

kx NULL