Question

I need to perform ‘n’ unions using mysqli (where n changes based on user input). For instance:

select a from b where a=c[1]
UNION
select a from b where a=c[2]
...
UNION
select a from b where a=c[n]

Is there anyway to do this iteratively? Something like that:
for(i=1;i

Note: I can only run select queries on the database

Answer 1

No need for union

For numeric a it would be

$c = array(1,2,3);
$c = array_filter(array_map('intval',$c));
$in = implode(',',$c);
$sql = "select a from b where a IN ($in)";

for strings idea is pretty the same.