How to select and echo MySQL data (one to many) using PHP

Question

This is my current code, it works fine with one problem.

$stmt = $conn->prepare("SELECT * FROM tmdb_movies JOIN genres ON genres.genres_tmdb_id=tmdb_movies.tmdb_id 
  ");
     // Then fire it up
     $stmt->execute();
     // Pick up the result as an array
     $result = $stmt->fetchAll();

    // Now you run through this array in many ways, for example
     foreach ($result as $row) {
    print "".$row["movie_title"]." ".$row["genres_name"] ."   ".$row["cast_name"] ."<br/>";
}

The thing is, I am trying to echo Movie Name and it's Genres.

What I want to echo:

The Dark Knight - Action, Crime, Drama

What the code echo:

The Dark Knight - Action

The Dark Knight - Crime

The Dark Knight - Drama

Screenshot of main movie table http://prntscr.com/fokwip

and Screenshot of genres movie table http://prntscr.com/fokwoy

Answer 1

To echo what you want you can change your sql query :

$stmt = $conn->prepare("SELECT *, GROUP_CONCAT(genres.genres_name SEPARATOR ', ') AS genre_concat FROM tmdb_movies JOIN genres ON genres.genres_tmdb_id=tmdb_movies.tmdb_id GROUP BY tmdb_movies.movie_title");

//  sql strict group by

$stmt = $conn->prepare("SELECT tmdb_movies.movie_title, tmdb_movies.cast_name, GROUP_CONCAT(DISTINCT genres.genres_name SEPARATOR ', ') AS genre_concat FROM tmdb_movies JOIN genres ON genres.genres_tmdb_id=tmdb_movies.tmdb_id GROUP BY tmdb_movies.movie_title, tmdb_movies.cast_name ORDER BY tmdb_movies.movie_title");

$stmt->execute();

$result = $stmt->fetchAll();

foreach ($result as $row) {
        print "".$row["movie_title"]." ".$row["genre_concat"] ."   ".$row["cast_name"] ."<br/>";}

GROUP_CONCAT allows to concat all the different genre for each unique movie title.

More Documentation :

GROUP BY : https://www.w3schools.com/sql/sql_groupby.asp

GROUP_CONCAT : https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_group-concat

Answer 2

You can use group by and group_cancat like that:

SELECT
    tmdb_movies.*, group_concat(genres.genres_name) as genres_names
FROM
    tmdb_movies 
JOIN 
    genres 
ON 
    genres.genres_tmdb_id=tmdb_movies.tmdb_id
GROUP BY 
    tmdb_movies.movie_id

And then prints it:

foreach ($result as $row) {
    echo "{$row['movie_title']} - {$row['genres_names']}<br/>";
}

Alternative SQL(it seems better than above sql):

SELECT
    tmdb_movies.*, temp.genres_names
FROM
    tmdb_movies 
JOIN 
    (
        SELECT 
            genres_tmdb_id, group_concat(genres_name) as genres_names 
        FROM 
            genres
        GROUP BY 
            genres_tmdb_id
    ) temp 
    ON 
       temp.genres_tmdb_id = tmdb_movies.tmdb_id

Hope this helps.