How to print child, father, mother from these two tables? - sql

Question

Below are the tables:
relation table
cid
pid
101
202
566
322
875
345
people table
id
name
gender
101
Riya
F
566
Aman
M
202
Rakesh
M
875
lucky
M
202
Reena
F
322
Raina
F
345
Rohit
M
322
Mohit
M
345
Meena
F
output
Child
Mother
Father
Riya
Reena
Rakesh
Aman
Raina
Mohit
Lucky
Rohit
Meena
I tried this:
SELECT mother,
father
FROM (
SELECT id,
name,
sum(
CASE
WHEN gender = 'F' THEN 1
ELSE 0) AS mother,
sum (
CASE
WHEN gender = 'M' THEN 1
ELSE 0) AS father
FROM people
INNER JOIN relation
ON people. id = relation.p_id
GROUP BY id,
name) t1
INNER JOIN relation
ON relation.p_id = t1.id
Please let me know the query, for how to fetch this output. this above query does not work, I am not able to figure how to output child also.

Answer 1

You must join relation to 2 copies of people.
The 1st copy will return the child's name and the 2nd copy will return the names of the parents.
Then group by child and use conditional aggregation to get the names of the parents in one row:
SELECT c.name Child,
MAX(CASE WHEN p.gender = 'F' THEN p.name END) Mother,
MAX(CASE WHEN p.gender = 'M' THEN p.name END) Father
FROM relation r
INNER JOIN people c ON c.id = r.cid
INNER JOIN people p ON p.id = r.pid
GROUP BY r.cid, c.name;
See the demo.

Answer 2

You can join twice and then PIVOT:
SELECT *
FROM (
SELECT c.name AS child,
p.name AS parent,
p.gender
FROM relations r
INNER JOIN people c
ON r.cid = c.id
INNER JOIN people p
ON r.pid = p.id
)
PIVOT (
MAX(parent) FOR gender IN (
'M' AS father,
'F' AS mother
)
)
Which, for the sample data:
CREATE TABLE people (id, name, gender) AS
SELECT 101, 'Riya', 'F' FROM DUAL UNION ALL
SELECT 566, 'Aman', 'M' FROM DUAL UNION ALL
SELECT 202, 'Rakesh', 'M' FROM DUAL UNION ALL
SELECT 875, 'lucky', 'M' FROM DUAL UNION ALL
SELECT 202, 'Reena', 'F' FROM DUAL UNION ALL
SELECT 322, 'Raina', 'F' FROM DUAL UNION ALL
SELECT 345, 'Rohit', 'M' FROM DUAL UNION ALL
SELECT 322, 'Mohit', 'M' FROM DUAL UNION ALL
SELECT 345, 'Meena', 'F' FROM DUAL;
CREATE TABLE relations (cid, pid) AS
SELECT 101, 202 FROM DUAL UNION ALL
SELECT 566, 322 FROM DUAL UNION ALL
SELECT 875, 345 FROM DUAL;
Outputs:
CHILD
FATHER
MOTHER
Riya
Rakesh
Reena
Aman
Mohit
Raina
lucky
Rohit
Meena
db<>fiddle here

Answer 3

Try this one
with cte as
(
select name as child, r.pid as pid
from people p
join relation r
on p.id=r.cid
)
select ee.child as child,
(select name from people PM where id=ee.pid and PM.gender='F') as Mother,
(select name from people PP where id=ee.pid and PP.gender='M') as Father
from cte ee

Answer 4

You can try below query -
SELECT P.name Child, p2.name mother, p3.name father
FROM relation R
JOIN people P ON R.cid = P.id
JOIN people P2 ON R.pid = P.id
AND P.gender = 'F'
JOIN people P3 ON R.pid = P.id
AND P.gender = 'M'

Answer 5

SELECT DISTINCT P1.NAME AS CHILD,(SELECT NAME FROM PEOPLE PM WHERE ID=T.PID AND PM.GENDER='F') AS MOTHER,
(SELECT NAME FROM PEOPLE PP WHERE ID=T.PID AND PP.GENDER='M') AS FATHER FROM
(SELECT R.CID,NAME,R.PID,P.GENDER FROM PEOPLE P,RELATIONS R
WHERE P.ID=R.PID) T,PEOPLE P1
WHERE T.CID=P1.ID;

Answer 6

select * from
(select * from
(select p.firstname as child, (select p1.firstname from persons p1 where r.p_id=p1.id and p1.gender='M') as father
from persons p inner join relations r on
p.id=r.id
) t
where t.father is not null
) as table1
inner join
(select * from
(select p.firstname as child, (select p1.firstname from persons p1 where r.p_id=p1.id and p1.gender='F') as mother
from persons p inner join relations r on
p.id=r.id
) t
where t.mother is not null ) as table2
on table1.child=table2.child

Answer 7

SELECT l.cid AS id,
r.NAME AS Child,
mother.NAME AS Mother,
father.NAME AS Father
FROM testdb.dbo.people r
JOIN testdb.dbo.relation l
ON l.cid = r.id
JOIN (SELECT l.cid AS id,
r.NAME
FROM testdb.dbo.people r
JOIN testdb.dbo.relation l
ON l.pid = r.id
AND gender = 'F') AS mother
ON l.cid = mother.id
JOIN (SELECT l.cid AS id,
r.NAME
FROM testdb.dbo.people r
JOIN testdb.dbo.relation l
ON l.pid = r.id
AND gender = 'M') AS father
ON l.cid = father.id

Answer 8

Query that prints the names of a child and his parents in individual columns respectively in order of the name of the child.
SELECT c.name as child,
MAX(CASE WHEN p.gender = 'F' THEN p.name END) AS mother,
MAX(CASE WHEN p.gender = 'M' THEN p.name END) AS father
FROM relations r
INNER JOIN public."People" c on c.id = r.cid
INNER JOIN public."People" p on p.id = r.pid
GROUP BY r.cid, c.name ORDER BY c.name;

Answer 9

select b.name as child,c.name as father,d.name as mother from relation a join people b on a.cid=b.id
join people c on a.pid=c.id
join people d on a.pid=d.id where c.gender='m' and d.gender='f'