Perform counting for number of occurrence in SQL - sql

Question

Is it common and convenient for SQL to perform such data manipulation, capturing only results in columns satisfying the conditions, and perform counting for number of occurrence? How to write SQL code to generate the desired output (if feasible).
Name is presented only when the conditions (Cond1 to Cond5) are yes.
Desired Input
ID Cond1 Cond2 Cond3 Cond4 Cond5 Name1 Name2 Name3 Name4 Name5
1 No Yes No No Yes (null) Result1 n/a (null) Result2
2 Yes No Yes No Yes Result3 n/a Result4 (null) Result5
Desired Output
ID Counting Name
1 1 Result1
1 2 Result2
2 1 Result3
2 2 Result4
2 3 Result5

Answer 1

This can be done with union all and row_number():
select id, row_number() over(partition by id order by seq) couting, name
from (
select id, name1 name, 1 seq from mytable where cond1 = 'Yes'
union all select id, name2, 2 from mytable where cond2 = 'Yes'
union all select id, name3, 3 from mytable where cond3 = 'Yes'
union all select id, name4, 4 from mytable where cond4 = 'Yes'
union all select id, name5, 5 from mytable where cond5 = 'Yes'
) x
order by id, rn

Answer 2

You can use UNPIVOT with pairs of columns and then filter on the Yes rows and use the ROW_NUMBER analytic function to get the incremental index of the result:
Query:
SELECT id,
ROW_NUMBER() OVER ( PARTITION BY id ORDER BY value ) AS "COUNT",
name
FROM table_name
UNPIVOT ( ( cond, name ) FOR value IN (
( Cond1, Name1 ) AS 'V1',
( Cond2, Name2 ) AS 'V2',
( Cond3, Name3 ) AS 'V3',
( Cond4, Name4 ) AS 'V4',
( Cond5, Name5 ) AS 'V5'
) )
WHERE cond = 'Yes'
Test Data:
CREATE TABLE table_name (
ID NUMBER(10,0) PRIMARY KEY,
Cond1 VARCHAR2(3) CHECK ( Cond1 IN ( 'Yes', 'No' ) ),
Cond2 VARCHAR2(3) CHECK ( Cond2 IN ( 'Yes', 'No' ) ),
Cond3 VARCHAR2(3) CHECK ( Cond3 IN ( 'Yes', 'No' ) ),
Cond4 VARCHAR2(3) CHECK ( Cond4 IN ( 'Yes', 'No' ) ),
Cond5 VARCHAR2(3) CHECK ( Cond5 IN ( 'Yes', 'No' ) ),
Name1 VARCHAR2(10),
Name2 VARCHAR2(10),
Name3 VARCHAR2(10),
Name4 VARCHAR2(10),
Name5 VARCHAR2(10),
CHECK ( ( Cond1 = 'Yes' AND Name1 IS NOT NULL ) OR ( Cond1 = 'No' AND ( Name1 IS NULL OR Name1 = 'n/a' ) ) ),
CHECK ( ( Cond2 = 'Yes' AND Name2 IS NOT NULL ) OR ( Cond2 = 'No' AND ( Name2 IS NULL OR Name2 = 'n/a' ) ) ),
CHECK ( ( Cond3 = 'Yes' AND Name3 IS NOT NULL ) OR ( Cond3 = 'No' AND ( Name3 IS NULL OR Name3 = 'n/a' ) ) ),
CHECK ( ( Cond4 = 'Yes' AND Name4 IS NOT NULL ) OR ( Cond4 = 'No' AND ( Name4 IS NULL OR Name4 = 'n/a' ) ) ),
CHECK ( ( Cond5 = 'Yes' AND Name5 IS NOT NULL ) OR ( Cond5 = 'No' AND ( Name5 IS NULL OR Name5 = 'n/a' ) ) )
);
INSERT INTO table_name ( ID, Cond1, Cond2, Cond3, Cond4, Cond5, Name1, Name2, Name3, Name4, Name5 )
SELECT 1, 'No', 'Yes', 'No', 'No', 'Yes', null, 'Result1', 'n/a', null, 'Result2' FROM DUAL UNION ALL
SELECT 2, 'Yes', 'No', 'Yes', 'No', 'Yes', 'Result3', 'n/a', 'Result4', null, 'Result5' FROM DUAL;
Output:
ID | COUNT | NAME
-: | ----: | :------
1 | 1 | Result1
1 | 2 | Result2
2 | 1 | Result3
2 | 2 | Result4
2 | 3 | Result5
db<>fiddle here

Answer 3

Another option:
SQL> with
2 test (id, cond1, cond2, cond3, cond4, cond5, name1, name2, name3, name4, name5) as
3 -- your sample data
4 (select 1, 'no' , 'yes', 'no' , 'no', 'yes', null , 'result1', 'n/a' , null, 'result2' from dual union all
5 select 2, 'yes', 'no' , 'yes', 'no', 'yes', 'result3', 'n/a' , 'result4', null, 'result5' from dual
6 ),
7 temp as
8 -- values whose COND column is 'yes'
9 (select id,
10 decode(cond1, 'yes', name1) n1,
11 decode(cond2, 'yes', name2) n2,
12 decode(cond3, 'yes', name3) n3,
13 decode(cond4, 'yes', name4) n4,
14 decode(cond5, 'yes', name5) n5
15 from test
16 ),
17 up as
18 -- unpivot data
19 (select *
20 from temp
21 unpivot (c_name for pc in (n1, n2, n3, n4, n5))
22 )
23 -- final result
24 select id,
25 row_number() over (partition by id order by c_name) counting,
26 c_name as name
27 from up
28 order by id;
ID COUNTING NAME
---------- ---------- -------
1 1 result1
1 2 result2
2 1 result3
2 2 result4
2 3 result5
SQL>

Answer 4

You can use CONNECT BY LEVEL for achieving the desired result as following:
SELECT
ID,
ROW_NUMBER() OVER(PARTITION BY ID ORDER BY LVL) AS "Counting",
NAME_ AS "Name"
FROM
(SELECT
T.ID,
DECODE(LVL, 1, COND1, 2, COND2, 3, COND3, 4, COND4, 5, COND5) AS COND,
DECODE(LVL, 1, NAME1, 2, NAME2, 3, NAME3, 4, NAME4, 5, NAME5) AS NAME_,
LVL AS LVL
FROM
YOUR_TABLE T join
(Select level as lvl from dual CONNECT BY LEVEL <= 5) on (1=1)
)
WHERE COND = 'Yes';
Cheers!!

Answer 5

Here is another option using UNPIVOT.
create table mytab(id number,
cond1 varchar2(3),
cond2 varchar2(3),
cond3 varchar2(3),
cond4 varchar2(3),
cond5 varchar2(3),
Name1 varchar2(7),
Name2 varchar2(7),
Name3 varchar2(7),
Name4 varchar2(7),
Name5 varchar2(7));
insert into mytab values(1,'No','Yes','No','No','Yes',null,'Result1','n/a',null,'Result2');
insert into mytab values(2,'Yes','No','Yes','No','Yes','Result3','n/a','Result4',null,'Result5');
commit;
select * from mytab;
Output:
ID COND1 COND2 COND3 COND4 COND5 NAME1 NAME2 NAME3 NAME4 NAME5
1 No Yes No No Yes (null) Result1 n/a (null) Result2
2 Yes No Yes No Yes Result3 n/a Result4 (null) Result5
UNPIVOT based solution.
with ns as (
select id,
n,
names
from mytab
unpivot(names for n in (name1 as 'n1',
name2 as 'n2',
name3 as 'n3',
name4 as 'n4',
name5 as 'n5'))),
cs as (
select id,
n,
condns
from mytab
unpivot(condns for n in (cond1 as 'n1',
cond2 as 'n2',
cond3 as 'n3',
cond4 as 'n4',
cond5 as 'n5')))
select ns.id,
row_number() over(partition by ns.id order by ns.n) counting,
ns.names
from ns inner join cs
on ns.id = cs.id
and ns.n = cs.n
and cs.condns = 'Yes'
order by 1,2;
Output:
ID COUNTING NAMES
1 1 Result1
1 2 Result2
2 1 Result3
2 2 Result4
2 3 Result5