SQL Oracle - CASE WHEN for separately ID's [closed] - sql

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I have some (thousands ;)) ID's and I'm trying check their relationship separately. But I have problem with checking relationship for each ID independently. Actualy my code check this for all ID`s beetwen them..
Table for example
ID Service
1 A
1 A1
2 A
2 B
3 A
3 A1
SQL code
SELECT a.ID, a.service,
CASE
WHEN a.service IN ('A','A1') THEN 'Yes'
ELSE 'No'
END
FROM t1 a
Output
ID Service RELATION
1 A YES
1 A1 YES
2 A NO
2 B NO
3 A YES
3 A1 YES

Answer 1

First, you should sort your table according to service alphabetically.
Then create an array and populate it with all the services:
DECLARE
CURSOR c_t1 is
SELECT service FROM t1;
type c_list is varray (6) of t1.service%type;
service_list c_list := c_list();
counter integer :=0;
BEGIN
FOR n IN c_t1 LOOP
counter := counter + 1;
service_list.extend;
service_list(counter) := n.service;
dbms_output.put_line('Service('||counter ||'):'||service_list(counter));
END LOOP;
END;
/
Then iterate through your table values:
DECLARE
v_count number DEFAULT 0;
BEGIN
FOR i IN (SELECT t1.ID, t1.service FROM t1)
LOOP
FOR j IN (service_list.COUNT)
LOOP
CASE
WHEN t1.service IN (service_list[i], service_list[i+1]) THEN 'Yes'
ELSE 'No'
END
v_COUNT := v_COUNT + 1;
END LOOP;
END LOOP;
DBMS_OUTPUT.PUT_LINE(v_COUNT);
END;
/

Answer 2

The following query works though I'm not sure how it would perform.
WITH a1
AS (SELECT id, 1 AS here
FROM services
WHERE service = 'A1')
, a
AS (SELECT id, 1 AS here
FROM services
WHERE service = 'A')
SELECT driver.id
, driver.service
, CASE
WHEN NVL(a1.here, 0) + NVL(a.here, 0) > 1 THEN 'YES'
ELSE 'NO'
END
FROM services driver
LEFT OUTER JOIN a1 ON a1.id = driver.id
LEFT OUTER JOIN a ON a.id = driver.id

Answer 3

But I have problem with checking relationship for each ID
independently
That is why it is suggested to you to create a new table storing all the unique relationships between the services. This gives you a better handle to compare the relations and give you the desired output.
You should start by creating the relationship table which stores values like this.
|rid| S1 | S2 |
--- |----|----|
|1 | A | A1 |
Now, to generate your desired output, you should first use a self join to get the pairs of relations with common IDs .
SELECT a.id,
a.service,
b.service
FROM t1 a
join t1 b
ON ( a.service != b.service
AND a.id = b.id ) ;
Once you have got such combinations, all you would need is to check if that combination of relation exists using an OUTER JOIN with relationship table, which will help you to get the output as "YES" or "NO" based on the existence.
SELECT a.id,
b.service,
CASE
WHEN r.id IS NULL THEN 'NO'
ELSE 'YES'
END AS relation
FROM t1 a
join t1 b
ON ( a.service != b.service
AND a.id = b.id )
left join rel r
ON ( ( r.s1 = a.service
AND r.s2 = b.service )
OR ( r.s2 = a.service
AND r.s1 = b.service ) );
Demo

Answer 4

I would use window function :
select t1.*, (case when sum(case when service not in ('A', 'A1') then 1 else 0 end) over (partition by id) = 0
then 'yes' else 'no'
end) as Relation
from t1;

Answer 5

this will work and you have to use decode function for it:
create table ex2(
no1 number,
no2 varchar(20));
insert into ex2 values(1, 'A');
insert into ex2 values(1 , 'A1');
insert into ex2 values(2 , 'A');
insert into ex2 values(2 , 'B');
insert into ex2 values(3 , 'A');
insert into ex2 values(3 , 'A1');
select * from ex2;
SELECT no1, no2 ,
decode(no2,'A','yes','A1','yes','no')
FROM ex2;
output:
1 A yes
2 A yes
2 B no
3 A yes
3 A1 yes
1 A1 yes
for your table query is :
SELECT ID, service ,
decode(service,'A','yes','A1','yes','no')
FROM ex2;