MySQL using AND in a single column [duplicate] - php

Question

This question already has answers here:
How to return rows that have the same column values in MySql
(3 answers)
Closed 5 years ago.
I'm working on a tag system where an array (of tags) is queried and all rows with the same tags in the Tag column are selected.
The issue is that I used the IN condition which is a type of an OR function, which selected all the rows with the same tags as opposed to narrowing them down, for example.
Instead of narrowing down an image with tags like 'sun' and 'landscape' it would select all images with those tags.
What I'm looking for is an AND version of IN () or a substitute that can work with arrays.
This is just an example. In reality, the user can add as many tags as they want
+----+---------+---------+
| ID | ImageID | Tag |
+----+---------+---------+
| 1 | 2 | sun |
+----+---------+---------+
| 2 | 12 |landscape|
+----+---------+---------+
| 3 | 15 | field |
+----+---------+---------+
| 4 | 15 |landscape|
+----+---------+---------+
My code
$tag = $_POST['tag'];
$tag = preg_split("#/#", $tag);
$tag = implode("', '", $tag);
$query = "SELECT * FROM ComicStripTags WHERE `Tag` IN ('$tag')";
$result = mysqli_query($link, $query);
while ($row = mysqli_fetch_array($result)){
$ID[] = $row['ImageID'];
}
Thanks
P.S. I'm not working in SQL, im working in PHP

Answer 1

You can do it using inner joins:
select * from TAGS a
inner join TAGS b
on a.ImageID = b.ImageID
where a.tag = 'field'
and b.tag = 'landscape'
According to your PHP code:
$joins = [];
$conditions = [];
foreach (preg_split("#/#", $_POST['tag']) as $index => $tag) {
$alias = "ComicStripTags_$index";
$joins[] = "ComicStripTags AS $alias" . ($index > 0 ? " ON ComicStripTags_0.ImageID = $alias.ImageID" : '');
$conditions[] = "$alias.Tag = '$tag'";
}
$query = sprintf("SELECT * FROM %s WHERE %s", implode(' INNER JOIN ', $joins), implode(' AND ', $conditions));

Answer 2

Assuming each ImageID can have only one of each tag, you can group by ImageID and select only rows where the count of tags equals the size of the input array.
SELECT ImageID FROM ComicStripTags
WHERE Tag IN ('landscape', 'field')
GROUP BY ImageID HAVING COUNT(Tag) = 2;

Answer 3

Alternatively you can do some ranking which would support partial tag matches as well:
SELECT
ImageID,
group_concat(Tag) as 'matched_tags',
count(*) as 'tag_matches'
FROM TAGS
WHERE Tag IN ( [list_of_tags] )
GROUP BY ImageID
HAVING tag_matches >= [minimum_number_of_tags]
ORDER BY tag_matches DESC