MySQL查询使用来自两个表的数据

Question

I have two tables like so:

Table 1: tracks
id  | artist     | track
---------------------------------------
1     Tom Smith    This Time is Right Time
2     Tom Smith    Oh Yes
3     John Doe     Every Time I See You

Table 2: festival_bands
id  | fest_title | fest_artist
---------------------------------------
1     Hoe Down Fest 2019    John Doe
2     Copperland Fest       Tom Smith
3     Copperland Fest       Reggie Wisk
4     Copperland Fest       Tom Smith
5     Copperland Fest       John Doe
6     Bluegrass Memories    John Doe

I need to show only ONE "track" from table 1 for each festival listing from Table 2 like so: Results:

Copperland Festival:
-----------------------
Tom Smith    This Time is Right Time
John Doe     Every Time I See You

In layman's terms, the logic would be along the lines of: Get only one track from TABLE 1 where artist equals (or matches) fest_artist from TABLE 2

I referenced a similar question which advised something in the direction of: $sql="select * from tracks WHERE (artist) in (select fest_artist from festival_bands group by name)" but with no luck.

Answer 1

You can use a correlated subquery to get a random track for the artist:

select fb.*,
       (select t.track
        from tracks t
        where t.artist = fb.fest_artist
        order by t.counter desc
       ) as most_popular_track
from festival_bands fb;