SQL to handle multiple AND conditions

I have the following data:

Institution_no
Cred_type

1
1

1
2

2
1

I have a list box so the user can select multiple Cred_type, they want to be able to select either OR or AND conditions.

For the OR I have like this AND CRED_TYPE IN (1,2)

For the AND, I am really scratching my head. What they are saying is they want a list of institutions that have cred type 1 and cred_type 2. Perhaps I'm not thinking clearly but this is row by row, so doing this would lead to no results.

AND cred_type = 1
AND cred_type = 2 -- you can't have a single row have two different values, this would return no results.

They require that the user can select 10, 20, or more, so writing out a bunch of code for each and combining them all would be really tough - but this is the only thought I had so far. It would be like this

Select institution_no from table where cred_type = 1
UNION 
Select institution_no from table where cred_type = 2

-- this would combine both and get me what I want, but you could imagine all the code for 10 or 20 of these.

You can use HAVING clause.

For example:
If you have a list of institutions that have cred type 1,2,3,4,5,6 you could try something like:

select institution_no 
from table 
where cred_type in (1,2,3,4,5,6)
group by institution_no
having count(distinct cred_type)=6;

EDIT: Query used by OP

with cte as ( 
             select distinct institution_no, 
                    CERT_TYPE 
             from credentialing 
             where CERT_TYPE in (1,2)
             ) 
select institution_no, 
       count(institution_no) 
from cte 
group by institution_no 
having count(institution_no) = 2;

StackExchange Database Administrators Q#306941, answer score: 6