SQL查询（Postgres）如何回答？

Question

I have a table with company id's (non unique) and some attribute (let's call it status id), status can be between 1 to 18 (many to many the row id is what unique) now I need to get results of companies who only have rows with 1 and 18, if they have any number as well (let's say 3) then this company should not be returned. The data is stored as row id, some meta data, company id and one status id, the example below is AFTER I ran a group by query.

So as an example if I do group by and string agg, I am getting these values:

Company ID Status
1           1,9,12,18
2           12,13,18
3           1
4           8
5           18

So in this case I need to return only 3 and 5.

Answer 1

You should fix your data model. Here are some reasons:

• Storing numbers in strings is BAD.
• Storing multiple values in a string is BAD.
• SQL has poor string processing capabilities.
• Postgres offers many ways to store multiple values -- a junction table, arrays, and JSON come to mind.

For your particular problem, how about an explicit comparison?

where status in ('1', '18', '1,18', '18,1')

Answer 2

You can group by companyid and set 2 conditions in the having clause:

select companyid
from tablename
group by companyid
having 
  sum((status in (1, 18))::int) > 0
  and
  sum((status not in (1, 18))::int) = 0

Or with EXCEPT :

select companyid from tablename
except
select companyid from tablename
where status not in (1, 18)

See the demo .
Results:

> | companyid |
> | --------: |
> |         3 |
> |         5 |

Answer 3

You can utilize group by and having. ie:

select * 
from myTable 
where statusId in (1,18)
and companyId in (select companyId 
  from myTable 
  group by companyId
  having count(distinct statusId) = 1); 

EDIT: If you meant to include those who have 1,18 and 18,1 too, then you could use array_agg instead:

select *
from t t1
inner join
     (select companyId, array_agg(statusId) as statuses
      from t
      group by companyId
     ) t2 on t1.companyid = t2.companyid
where array[1,18] @> t2.statuses;

EDIT: If you meant to get back only companyIds without the rest of columns and data:

select companyId
      from t
      group by companyId
      having array[1,18] @> array_agg(statusId);

DbFiddle Demo