I need the count of values - sql

Question

I have data in my table in oracle like below
A_CODE B_M P_id
------ ---- ------
123 A 1
123 A 2
123 B 5
678 B 3
678 C 3
678 B 4
123 BC 2
The value "BC" is B and C. The data is not normalized so we need to count it as B and C. I need the counts to be displayed as below per A_CODE
A_CODE B_M COUNT
------- ---- -------
123 A 2
123 B 2
123 C 1
678 B 2
678 C 1
How can i do this in Oracle?

Answer 1

You should use CONNECT BY and CONNECT_BY_ROOT.
I hope this helps:
SELECT A_CODE, B_M, COUNT (*)
FROM ( SELECT A_CODE, SUBSTR (CONNECT_BY_ROOT (B_M), LEVEL, 1) B_M
FROM your_table
CONNECT BY LEVEL <= LENGTH (B_M))
WHERE B_M IS NOT NULL
GROUP BY A_CODE, B_M
ORDER BY A_CODE;

Answer 2

Please try below:
SELECT A_CODE, B_M, COUNT(*) "COUNT" FROM
(SELECT A_CODE, B_M
FROM
(SELECT A_CODE,
SUBSTR(B_M,x.LVL,1) B_M
FROM my_table t,
(SELECT LEVEL LVL FROM dual
CONNECT BY LEVEL <=
(SELECT MAX(LENGTH(B_M)) FROM my_table)
) x
WHERE t.B_M is not null
)
WHERE B_M IS NOT NULL
UNION ALL
SELECT A_CODE, B_M FROM my_table WHERE B_M IS NULL
)
GROUP BY A_CODE,
B_M
ORDER BY A_CODE, B_M;

Answer 3

One option is to join this table to a data set that provides you with the normalised structure you need.
with cte_normaliser as (
select 'A' B_M, 'A' 'B_M_norm from dual union all
select 'B' B_M, 'B' 'B_M_norm from dual union all
select 'C' B_M, 'C' 'B_M_norm from dual union all
select 'BC' B_M, 'B' 'B_M_norm from dual union all
select 'BC' B_M, 'C' 'B_M_norm from dual)
select my_table.A_CODE,
n.B_M_norm,
count(*)
from my_table join
cte_normaliser n on n.B_M = my_table.B_M
group by my_table.A_CODE,
n.B_M_norm;
Using a fixed data set like that might not be feasible if you have a large number of variable code combination, though, and that data set might need to be built dynamically.

Answer 4

Besides having my_table, you create a table with all possible values. That is:
P_VAL
-----
A
B
C
Then, you should be able to obtain the count of occurrences with a join. Something like:
with my_table
as ( select '123' a_code, 'A' b_m, '1' p_id from dual
union select '123' a_code, 'A' b_m, '2' p_id from dual
union select '123' a_code, 'B' b_m, '5' p_id from dual
union select '678' a_code, 'B' b_m, '3' p_id from dual
union select '678' a_code, 'C' b_m, '3' p_id from dual
union select '678' a_code, 'B' b_m, '4' p_id from dual
union select '123' a_code, 'BC' b_m, '2' p_id from dual)
,possible_values
as ( select 'A' p_val from dual
union select 'B' p_val from dual
union select 'C' p_val from dual)
select a_code
,p_val b_m
,count('X') count
from my_table
join possible_values
on instr(b_m,p_val) > 0
group by a_code,p_val
order by a_code,p_val;