My page receives the conditions as strings in an array from somewhere I can’t change. The array values look like this:

$array_conditions[0] = column1 IN (1, 2, 3, 4)

I have a loop set up to go through these conditions and build the query string, which ends up looking like this:

SELECT * FROM table WHERE column1 IN (1, 2, 3, 4) AND column2 IN (1, 2, 3, 4)

So, The issue is, that array can sometimes contain two conditions under the same column name. There are way too many possible columns so I can’t treat each individually, and column names can possibly repeat any number of times.

$array_conditions[0] = column1 IN (1, 2, 3, 4)
$array_conditions[1] = column2 IN (1, 2, 3)
$array_conditions[2] = column1 IN (4, 5, 6)

SELECT * FROM table WHERE column1 IN (1, 2, 3, 4) AND column2 IN (1, 2, 3) AND column1 IN (4, 5, 6)

How would I go about to get an output like one of these two?

SELECT * FROM table WHERE column1 IN (1, 2, 3, 4, 5, 6) AND column2 IN (1, 2, 3)

SELECT * FROM table WHERE (column1 IN (1, 2, 3, 4) OR column1 IN (4, 5, 6)) AND column2 IN (1, 2, 3)

After a bit of searching on PHP functions, I realized regex might be the way to solve this. But I didn’t know any regex at all. I tried searching for some solutions online and even studying regex for a while but I haven’t come across the solution I’ve been looking for. All threads I could find could be solved by something like:

(?<=,|^)([^,]*)(?=.*\b\1\b)(?=,|$)

But a solution like this wouldn’t be enough, because I still need to either keep the values inside the parenthesis or keep the whole condition, bring it next to the other condition with the same column name then replace the “AND” with an “OR”

Best thing I managed to get was out from ChatGPT. I can’t undestand a thing about it and it can only replace one condition with two matches at a time. I tried coming up with a loop to replace it as many times as needed but I couldn’t figure out a way to make it run only if there were still duplicates.

$sql = preg_replace_callback('/(w+)s+ins+((d+(,s*d+)*)).*?1s+ins+((d+(,s*d+)*)/', 
function($matches) {return "({$matches[1]} in ({$matches[2]}) or {$matches[1]} in ({$matches[4]}))";}, $sql);