Converting MySQL code to Access: GROUP_CONCAT and a triple JOIN

问题

I'm having a really hard time translating a piece of MySQL-code to Access. I'm trying to use one of the queries found in the Sakila (MySQL) Database for an Access project I'm working on.

First of all, the GROUP_CONCAT function doesn't work at all. After some Google searches I found out that Access doesn't support this function but I couldn't find a working alternative. CONCAT however could be replaced by a few '+' operators.

Then comes the triple LEFT JOIN which kept returning a missing operator error. I found a blog post explaining how a series of brackets could help, but this resulted in even more trouble and prompted me to remove the brackets after which it threw more missing operator errors.

Also, SEPARATOR doesn't seem to be accepted as well, but this could be due to GROUP_CONCAT not functioning.

Is there anyone willing to get me in the right direction? I've been struggling with this for way too long.

SELECT
a.actor_id,
a.first_name,
a.last_name,
GROUP_CONCAT(DISTINCT CONCAT(c.name, ': ',
    (SELECT GROUP_CONCAT(f.title ORDER BY f.title SEPARATOR ', ')
                FROM film f
                INNER JOIN film_category fc
                  ON f.film_id = fc.film_id
                INNER JOIN film_actor fa
                  ON f.film_id = fa.film_id
                WHERE fc.category_id = c.category_id
                AND fa.actor_id = a.actor_id
             )
         )
         ORDER BY c.name SEPARATOR '; ')
AS film_info
FROM
actor AS a
LEFT JOIN film_actor AS fa ON a.actor_id = fa.actor_id
LEFT JOIN film_category AS fc ON fa.film_id = fc.film_id
LEFT JOIN category AS c ON fc.category_id = c.category_id
GROUP BY a.actor_id, a.first_name, a.last_name

回答1:

The most commonly-cited Access alternative to the MySQL GROUP_CONCAT() function is Allen Browne's ConcatRelated() function, available here.

As for parentheses around JOINs, yes, Access SQL is fussy about those. Instead of

FROM
actor AS a
LEFT JOIN film_actor AS fa ON a.actor_id = fa.actor_id
LEFT JOIN film_category AS fc ON fa.film_id = fc.film_id
LEFT JOIN category AS c ON fc.category_id = c.category_id

try

FROM 
    (
        (
            actor AS a 
            LEFT JOIN 
            film_actor AS fa 
                ON a.actor_id = fa.actor_id
        ) 
        LEFT JOIN 
        film_category AS fc 
            ON fa.film_id = fc.film_id
    ) 
    LEFT JOIN 
    category AS c 
        ON fc.category_id = c.category_id

来源：https://stackoverflow.com/questions/19478272/converting-mysql-code-to-access-group-concat-and-a-triple-join

标签

mysql

ms-access

group-concat