INSERT INTO, Multiple WHERE IN, Check if value exist - php

Question

I am collecting information about 30 posts with title and content in a multidimensional array which is relatively long and then put all of them into database by one MySQL query. But my checking query is separate from that inserting. I am checking similar post by the new post's title and then insert it. How can I merge the checking query with the inserting one?
This is my multidimensional array about 30 posts :
array(
[0] => array(
[post_title] => $postTitle1,
[post_content] => $contentTitle1,
)
[1] => array(
[post_title] => $postTitle2,
[post_content] => $contentTitle2,
)
[N] => array(
[post_title] => $postTitleN,
[post_content] => $contentTitleN,
)
);
This is my checking query by the new post's title (is done for each post and works fine):
SELECT post_title FROM x_post WHERE post_title=$newPostTitle
This is my inserting query (works fine):
INSERT INTO x_post (`post_title`, `post_content`, `date_created`, `user_id`)
VALUES ((((( My multidimensional array's information will be here after processing )))))
and Finally this is the query what I want to have but it does not work (to merge two queries):
INSERT INTO x_post (`post_title`, `post_content`, `date_created`, `user_id`)
SELECT * FROM (SELECT $postTitle1, $content1, $time, $userId") AS tmp1, (SELECT $postTitle2, $content2, $time, $userId") AS tmp2, .......... and so on ........... , (SELECT $postTitle30, $content30, $time, $userId") AS tmp30 WHERE NOT EXIST (SELECT x_post.post_title FROM x_post WHERE x_post.post_title IN ($newPostTitle1, $newPostTitle2, ... and so on... , $newPostTitleN))
What is the best way to write the query ?
In fact I want to check all the 30 posts if similar is exist in one query and then insert those has not similar.
I know it is complicated, but would be a great query.
Thanks a lot.

Answer 1

You can use UNION ALL to make a set of your individual FROM-less SELECTs which you can then use as just one derived table instead of 30. And instead of using IN in the WHERE clause you can just correlate directly.
INSERT INTO x_post
(`post_title`,
`post_content`,
`date_created`,
`user_id`)
SELECT `post_title`,
`post_content`,
`date_created`,
`user_id`
FROM (SELECT $postTitle1 `post_title`,
$content1 `post_content`,
$time `date_created`,
$userId `user_id`
UNION ALL
...
UNION ALL
SELECT $postTitle30 `post_title`,
$content30 `post_content`,
$time `date_created`,
$userId `user_id`) tmp
WHERE NOT EXISTS (SELECT *
FROM x_news
WHERE x_news.news_title = tmp.`post_title`);