I'm struggling with the WHERE IN query - php

Question

I am not able to use this code. I've echoed the implode (and it works perfectly) but I cannot seem to get it to work with the WHERE IN query.
I've tried echo the import, which works, and the code works perfectly when I remove the WHERE IN, so I know the elements within 'etc etc' are working, too.
$filter_category = "SELECT * FROM `youcard_wp`.`bc_term_relationships`
WHERE term_taxonomy_id = '57'";
$result_c = $conn90->query($filter_category);
while($row_c = $result_c->fetch_assoc()){
$category_filter[] = $row_c['object_id'];
}
echo implode(',', $category_filter); // <- works great
$get_offer_list = "
SELECT * FROM `youcard_wp`.`bc_posts`
WHERE `ID` IN ('".implode(',', $category_filter)."')
AND post_status = 'publish'
AND post_type = 'portfolio'
ORDER BY menu_order ASC
";
$result = $conn90->query($get_offer_list);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
etc etc etc...

Answer 1

You don't need any of that. Instead use this...
SELECT x.columns
, x.you
, x.actually
, x.want
FROM bc_posts x
JOIN bc_term_relationships y
ON y.object_id = x.id
WHERE x.post_status = 'publish'
AND x.post_type = 'portfolio'
AND y.term_taxonomy_id = 57
ORDER
BY x.menu_order ASC

Answer 2

You are surrounding the whole IN list with a pair of single quotes, whereas you would need to quote each individual value.
Consider:
$get_offer_list = "
SELECT *
FROM `youcard_wp`.`bc_posts`
WHERE
`ID` IN ('" .implode("','", $category_filter)."')
AND post_status = 'publish'
AND post_type = 'portfolio'
ORDER BY menu_order ASC
";
If IDs are actually numeric values and not strings, then you do not need quotes at all:
$get_offer_list = "
SELECT *
FROM `youcard_wp`.`bc_posts`
WHERE
`ID` IN (" .implode(",", $category_filter).")
AND post_status = 'publish'
AND post_type = 'portfolio'
ORDER BY menu_order ASC
";