How to Fix MySQL's 'LIMIT & IN/ALL/ANY/SOME Subquery' Error?

MySQL: Addressing 'LIMIT & IN/ALL/ANY/SOME Subquery' Error

When using MySQL, you may encounter the error "This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'". This error typically occurs when attempting to use a subquery with a LIMIT clause and certain set operators, such as IN.

Consider the following PHP code:

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

This code attempts to retrieve a random video from a set of videos that contain a specific string in their title. However, MySQL versions that do not support the 'LIMIT & IN/ALL/ANY/SOME subquery' syntax will fail with the aforementioned error.

Solution: Replacing IN with JOIN

To resolve this issue, you can replace the IN operator with a JOIN statement. This can be achieved using the following code:

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 modified query, we use an INNER JOIN to link the two tables, ensuring that only matching video IDs are selected. The JOIN operation replaces the IN operator, enabling the query to execute successfully even on MySQL versions that do not support 'LIMIT & IN/ALL/ANY/SOME subquery'.

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