SQL Server : SELECT ID having only a single condition - sql

Question

I have a patients table with details such as conditions that the patient has. from the below table I want to select Patients, Claims which have ONLY a single condition - 'Hypertension'. Example Patient B is the expected output. Patient A will not be selected because he claimed for multiple conditions.
+----+---------+--------------+
| ID | ClaimID | Condition |
+----+---------+--------------+
| A | 14234 | Hypertension |
| A | 14234 | Diabetes |
| A | 63947 | Diabetes |
| B | 23853 | Hypertension |
+----+---------+--------------+
I tried using the NOT IN condition as below but doesn't seem to help
SELECT ID, ClaimID, Condition
FROM myTable
WHERE Condition IN ('Hypertension')
AND Condition NOT IN ('Diabetes')

Answer 1

One method uses not exists:
select t.*
from mytable t
where t.condition = 'Hypertension' and
not exists (select 1
from mytable t2
where t2.id = t.id and t2.condition <> t.condition
);

Answer 2

Or you can do it like this:
select
id,
claim_id,
condition
from
patient
where
id in
(
select
id
from
patient
group by
id having count (distinct condition) = 1
);
Result:
id claim_id condition
-- ----------- ----------------
B 23853 Hypertension
(1 rows affected)
Setup:
create table patient
(
id varchar(1),
claim_id int,
condition varchar(16)
);
insert into patient (id, claim_id, condition) values ('A', 14234, 'Hypertension');
insert into patient (id, claim_id, condition) values ('A', 14234, 'Diabetes');
insert into patient (id, claim_id, condition) values ('A', 63947, 'Diabetes');
insert into patient (id, claim_id, condition) values ('B', 23853, 'Hypertension');

Answer 3

You can do this with a CTE.
I set up this CTE with two parameters, one being the Condition you seek, and the other being the max number of combined conditions to find (in your case 1).
DECLARE #myTable TABLE (Id VARCHAR(1), ClaimID INT, Condition VARCHAR(100))
INSERT INTO #myTable (Id, ClaimID, Condition)
SELECT 'A',14234,'Hypertension' UNION ALL
SELECT 'A',14234,'Diabetes' UNION ALL
SELECT 'A',63947,'Diabetes' UNION ALL
SELECT 'B',23853,'Hypertension'
DECLARE #Condition VARCHAR(100)
DECLARE #MaxConditions TINYINT
SET #Condition='Hypertension'
SET #MaxConditions=1
; WITH CTE AS
(
SELECT *, COUNT(2) OVER(PARTITION BY ClaimID) AS CN
FROM #myTable T1
WHERE EXISTS (SELECT 1 FROM #myTable T2 WHERE T1.ClaimID=T2.ClaimID AND T2.Condition=#Condition)
)
SELECT *
FROM CTE
WHERE CN<=#MaxConditions
If you don't care about the fluff, and just want all ClaimID's with just ONE condition regardless of which condition it is use this.
DECLARE #myTable TABLE (Id VARCHAR(1), ClaimID INT, Condition VARCHAR(100))
INSERT INTO #myTable (Id, ClaimID, Condition)
SELECT 'A',14234,'Hypertension' UNION ALL
SELECT 'A',14234,'Diabetes' UNION ALL
SELECT 'A',63947,'Diabetes' UNION ALL
SELECT 'B',23853,'Hypertension'
DECLARE #MaxConditions TINYINT
SET #MaxConditions=1
; WITH CTE AS
(
SELECT *, COUNT(2) OVER(PARTITION BY ClaimID) AS CN
FROM #myTable T1
)
SELECT *
FROM CTE
WHERE CN<=#MaxConditions

Answer 4

Here is one method using Having clause
SELECT t.*
FROM mytable t
WHERE EXISTS (SELECT 1
FROM mytable t2
WHERE t2.id = t.id
HAVING Count(CASE WHEN condition = 'Hypertension' THEN 1 END) > 0
AND Count(CASE WHEN condition != 'Hypertension' THEN 1 END) = 0)

Answer 5

And yet a couple of other ways to do this:
declare #TableA table(Id char,
ClaimId int,
Condition varchar(250));
insert into #TableA (id, claimid, condition)
values ('A', 14234, 'Hypertension'),
('A', 14234, 'Diabetes'),
('A', 63947, 'Diabetes'),
('B', 23853, 'Hypertension')
select id, claimid, condition
from #TableA a
where not exists(select id
from #TableA b
where a.id = b.id
group by b.id
having count(b.id) > 1)
OR
;with cte as
(
select id, claimid, condition
from #TableA
)
,
cte2 as
(
Select id, count(Id) as counts
from cte
group by id
having count(id) < 2
)
Select cte.id, claimid, condition
From cte
inner join
cte2
on cte.id = cte2.id

Answer 6

I decided to revise my answer into an appropriate one.
A simple solution to your question is to count the rows instead of the ID values (since it's not an integer).
Here is a simple introduction:
SELECT
ID
FROM
#PatientTable
GROUP BY
ID
HAVING
ID = ID AND COUNT(*) = 1
This will Return the ID B
+----+
| ID |
+----+
| B |
+----+
Surely, this is not enough, as you may work with a large data and need more filtering.
So, we will go and use it as a sub-query.
Using it as a sub-query it's simple :
SELECT
ID,
ClaimID,
Condition
FROM
#PatientTable
WHERE
ID = (SELECT ID AS NumberOfClaims FROM #PatientTable GROUP BY ID HAVING ID = ID AND COUNT(*) = 1)
This will return
+----+---------+--------------+
| ID | ClaimID | Condition |
+----+---------+--------------+
| B | 23853 | Hypertension |
+----+---------+--------------+
So far so good, but there is another issue we may face. Let's say you have a multiple Claims from a multiple patients, using this query as is will only show one patient. To show all patients we need to use IN rather than = under the WHERE clause
WHERE
ID IN (SELECT ID AS NumberOfClaims FROM #PatientTable GROUP BY ID HAVING ID = ID AND COUNT(*) = 1)
This will list all patients that falls under this condition.
If you need more conditions to filter, you just add them to the WHERE clause and you'll be good to go.

Answer 7

SELECT id, sum(ct)
FROM (SELECT customer_id, CASE WHEN category = 'X' THEN 0 else 1
end ct
FROM MASTER_TABLE
) AS t1
GROUP BY id
HAVING sum(ct) = 0
id which will have sum(ct) more than 1, will have multiple conditions

Answer 8

Use joins instead of subquery. Joins are always better in performance. You can use below query.
SELECT T1.id, T1.claimid, T1.Condition
FROM mytable T1
INNER JOIN
(
select id, count(Condition) counter
from mytable
group by id HAVING COUNT(DISTINCT CONDITION)=1
) T2 ON T1.ID=T2.ID
WHERE T2.counter=1