SQL select statement that returns records where a set of events have occurred more than once on the same ID - sql

Question

Say I have a table:
CREATE TABLE births
(
childid INT,
momid INT,
eclampsia VARCHAR(1),
preeclampsia VARCHAR(1),
hypertension VARCHAR(1)
);
Insert records:
INSERT INTO BIRTHS (CHILDID, MOMID, ECLAMPSIA)
VALUES (654321, 123456, 'Y'),
(654321, 123456, 'Y'),
INSERT INTO BIRTHS (CHILDID, MOMID, HYPERTENSION)
VALUES (987652, 465468, 'Y'),
(987987, 465468, 'Y')
INSERT INTO BIRTHS (CHILDID, MOMID)
VALUES (687765, 465468)
INSERT INTO BIRTHS (CHILDID, MOMID, PREECLAMPSIA)
VALUES (649870, 846587, 'Y')
INSERT INTO BIRTHS (CHILDID, MOMID)
VALUES (787463, 846587);
I want to return records for all mothers who have had more than one child and have had one of these three diagnoses in more than one pregnancy.
My expected results are:
child momid eclampsia preeclampsia hypertension
-------------------------------------------------------------
654321 123456 Y
431265 123456 Y
987652 465468 Y
987987 465468 Y
How would I do write this?
I have a sloppy query that does not quite do what I want. It works to some degree, but still gives me records where the momid has had a diagnosis only for one pregnancy.
select distinct
a.*, b.eclampsia, b.preeclampsia, b.hypertension
from
births a
join
births b on a.momid = b.momid
where
a.childid != b.childid
and a.eclampsia = 'y'
and (b.eclampsia = 'y' or b.preeclampsia = 'y' or b.hypertension = 'y')
or a.preeclampsia = 'y'
and (b.preeclampsia = 'y' or b.eclampsia = 'Y' or b.hypertension = 'y')
or a.hypertension = 'y'
and (b.hypertension = 'y' or b.eclampsia = 'y' or b.preeclampsia = 'y')
order by
mapersonid

Answer 1

I would solve your problem with this query:
SELECT * FROM births
WHERE momid IN(
SELECT momid FROM births GROUP BY momid
HAVING COUNT(1) >1 AND
SUM(CASE WHEN eclampsia = 'Y' THEN 1 WHEN preeclampsia = 'Y' THEN 1 WHEN hypertension = 'Y' THEN 1 ELSE 0 END) > 1)
AND (eclampsia = 'Y' OR preeclampsia = 'Y' OR hypertension = 'Y')
Basicly, you filter the momids via grouping and formulate your conditions within the HAVING clause and then using this list of momids to build your desired output.

Answer 2

This is one way of doing it. It counts records in the births table which display one of the symptoms for each mother, using that count > 1 as a condition to display the record, as long as the record also shows one of the conditions:
SELECT childid, momid,
COALESCE(eclampsia, '') AS eclampsia,
COALESCE(preeclampsia, '') AS preeclampsia,
COALESCE(hypertension, '') AS hypertension
FROM births b1
WHERE (SELECT COUNT(*) FROM births b2 WHERE b2.momid = b1.momid AND
(ECLAMPSIA = 'Y' OR PREECLAMPSIA = 'Y' OR HYPERTENSION = 'Y')
GROUP BY momid) > 1 AND
(ECLAMPSIA = 'Y' OR PREECLAMPSIA = 'Y' OR HYPERTENSION = 'Y')
Output
child momid eclampsia preeclampsia hypertension
654321 123456 Y
431265 123456 Y
987652 465468 Y
987987 465468 Y

Answer 3

First get the total complications for each mom using CTE and CASEexpression , then join the CTE with Births table on Momid, then filter the moms who have more than one complication. Something like below -
;WITH BirthCTE as(
Select momid,
SUM(CASE WHEN ECLAMPSIA = 'Y' OR PREECLAMPSIA = 'Y' OR HYPERTENSION = 'Y' THEN 1 ELSE 0 END) As TotalComl
FROM births
GROUP BY momid
)
select b.* from births b
inner join BirthCTE cte on b.momid = cte.momid
Where TotalComl > 1 -- More than one complication
and (ECLAMPSIA = 'Y' OR PREECLAMPSIA = 'Y' OR HYPERTENSION = 'Y') -- atleast one complication

Answer 4

This is the wrong data structure. You want a table of births with no complications. Then you want a table birthComplications with one row per complication, if any.
You can restructure the data on the fly. And then aggregation:
select b.momid
from births b outer apply
(select v.complication
from (values ('eclampsia', b.eclampsia), ('hypertension', b.hypertension), ('preeclampsia', b.preeclampsia)
) v(complication, flag)
where flag = 'y'
)
group by b.momid
having count(*) > 1 and -- more than one pregnancy
count(distinct case when v.complication is not null then b.childid end) > 1;
Actually, you can simplify the logic to moms who have had complications in more than one pregnancy. This looks like:
select b.momid
from births b apply -- only keep pregnancies with complications
(select v.complication
from (values ('eclampsia', b.eclampsia), ('hypertension', b.hypertension), ('preeclampsia', b.preeclampsia)
) v(complication, flag)
where flag = 'y'
)
group by b.momid
having count(distinct b.childid) > 1;

Answer 5

try this
select momid, count(*) as "children",
count(eclampsia) as "eclampsia",
count(preeclampsia) as "preeclampsia",
count(hypertension) as "hypertension"
from births
group by momid
having count(*) > 1 and
(
count(eclampsia) > 1 or
count(preeclampsia) > 1 or
count(hypertension) > 1
);
you will get something like: