I am running this query, and I am getting ** #1241 - Operand should contain 1 column(s)** error:
SELECT `forumCategories`.`id`, `forumCategories`.`name`, `forumCategories`.`order`, `forumCategories`.`description`, `forumCategories`.`date_created`, COUNT(forumPosts.forumCategory_id) as postCount,
(SELECT `forumPosts`.*, `forumChildPosts`.`id`, `forumChildPosts`.`forumPost_id`, COUNT(forumChildPosts.forumPost_id) as childCount FROM `forumChildPosts` LEFT JOIN `forumPosts` ON `forumPosts`.`id` = `forumChildPosts`.`forumPost_id` GROUP BY `forumPosts`.`id`) AS childCount
FROM `forumCategories`
LEFT JOIN `forumPosts` ON `forumCategories`.`id` = `forumPosts`.`forumCategory_id`
GROUP BY `forumCategories`.`id`
ORDER BY `forumCategories`.`order` DESC
I have 3 tables:
forumCategories
forumPosts | forumPosts.forumCategory_id = forumCategories.id
forumChildPosts | forumChildPosts.forumPosts_id = forumPosts.id
I want to count all posts for the forum category, and them I want to count all the child posts that belongs to that forum category. How can I do this?
You can't select several items with a subselect and then give them one name. Now you're getting everything from forumPosts, something from forumChildPosts etc and trying to put that into a single column, childCount. This is not allowed.
It might be enough to remove all other result columns from that select and only leave the count
?
I couldn't try it, is that makes sense ? But you can't get nested results from mysql due to its limitation, MYSQL is a Matrix table.
SELECT `forumCategories`.`id`,
`forumCategories`.`name`,
`forumCategories`.`order`,
`forumCategories`.`description`,
`forumCategories`.`date_created`,
COUNT(forumPosts.forumCategory_id) AS postCount,
(SELECT COUNT(forumChildPosts.forumPost_id) AS childCount FROM `forumChildPosts` LEFT JOIN `forumPosts` ON `forumPosts`.`id` = `forumChildPosts`.`forumPost_id` GROUP BY `forumPosts`.`id`) AS childCount
FROM `forumCategories`
LEFT JOIN `forumPosts` ON `forumCategories`.`id` = `forumPosts`.`forumCategory_id`
GROUP BY `forumCategories`.`id`
ORDER BY `forumCategories`.`order` DESC
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.