How to Work Around MySQL's Subquery LIMIT Restriction with IN Operator?

MySQL Incompatibility with Subquery Limits

The error message "This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'" indicates that the MySQL version being used does not support using a LIMIT clause within a subquery when using certain operators like IN.

Solution

One workaround for this limitation is to use a JOIN instead of an IN subquery. The following code demonstrates this approach:

$Last_Video = $db->fetch_all('
SELECT v.VID, v.thumb
FROM video AS v
INNER JOIN
     (SELECT VID
     FROM video
     WHERE title LIKE "%' . $Channel['name'] . '%"
     ORDER BY viewtime DESC
     LIMIT 5) AS v2
  ON v.VID = v2.VID
ORDER BY RAND()
LIMIT 1
');

In this code:

• A table alias "v" is used for the outer "video" table.
• A subquery is used to select the VIDs of videos matching the title filter and order them by view time in descending order. This subquery is aliased as "v2".
• A JOIN clause is used to join the main "video" table with the "v2" subquery on the VID column.
• The final result is limited to one randomly selected record using RAND() and LIMIT.

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