如何使用PHP在MySQL中过滤数据（一对多关系）

Question

What I Want To Do

The user will send a value using GET and I will store the value in a variable named $category1 . Now all the rows which contain the value of $category1 will display. This is like a search system.

This is my code

$stmt = $conn->prepare("SELECT tmdb_movies.movie_title
,GROUP_CONCAT(DISTINCT genres.genres_name SEPARATOR ', ') AS genres

FROM tmdb_movies

JOIN genres ON genres.genres_tmdb_id=tmdb_movies.tmdb_id

WHERE EXISTS (SELECT genres.genres_name FROM genres WHERE genres.genres_name = '$category1');

GROUP BY tmdb_movies.movie_title");

Error: Because of WHERE Exist line (IDK, if I should use it or no)

Fatal error: Uncaught PDOException: SQLSTATE[42000]: Syntax error or access violation: 1140 In aggregated query without GROUP BY, expression #1 of SELECT list contains nonaggregated column 'DataBaseName.tmdb_movies.movie_title'; this is incompatible with sql_mode=only_full_group_by

Let me explain my Table Structure now

I have two tables

1. tmdb_movies (it store movie title and tmdb_id)
2. genres (It stores genres, which is connected via tmdb_id)

The example of tables.

tmdb_movies table

tmdb_id     movie_title
1           The_Dark_Night
2           Logan
3           IronMan

genres table

tmdb_id       genres
 1            Action
 1            Crime
 1            Drama
 2            Action
 2            Drama
 3            Action
 3            Comedy

Answer 1

In 5.7 the sqlmode is set by default to:

ONLY_FULL_GROUP_BY,
 NO_AUTO_CREATE_USER,
 STRICT_TRANS_TABLES,
 NO_ENGINE_SUBSTITUTION

To remove the clause ONLY_FULL_GROUP_BY you can do this:

SET sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''));

This supposed you need to make that GROUP BY with non aggregated columns.

otherwise i tested your code locally it working perfectly fine.