Oracle SQL - return the date record when there is no count result - sql

Question

I have the tables below and I need my query to bring me the amount of operations grouped by date.
For the dates on which there will be no operations, I need to return the date anyway with the zero count.
Kind like that:
OPERATION_DATE | COUNT_OPERATION | COUNT_OPERATION2 |
04/06/2019 | 453 | 81 |
05/06/2019 | 0 | 0 |
-- QUERY I TRIED
SELECT
T1.DATE_OPERATION AS DATE_OPERATION,
NVL(T1.COUNT_OPERATION, '0') COUNT_OPERATION,
NVL(T1.COUNT_OPERATION2, '0') COUNT_OPERATIONX,
FROM
(
SELECT
trunc(t.DATE_OPERATION) as DATE_OPERATION,
count(t.ID_OPERATION) AS COUNT_OPERATION,
COUNT(CASE WHEN O.OPERATION_TYPE = 'X' THEN 1 END) COUNT_OPERATIONX,
from OPERATION o
left join OPERATION_TYPE ot on ot.id_operation = o.id_operation
where ot.OPERATION_TYPE in ('X', 'W', 'Z', 'I', 'J', 'V')
and TRUNC(t.DATE_OPERATION) >= to_date('01/06/2019', 'DD-MM-YYYY')
group by trunc(t.DATE_OPERATION)
) T1
-- TABLES
CREATE TABLE OPERATION
( ID_OPERATION NUMBER NOT NULL,
DATE_OPERATION DATE NOT NULL,
VALUE NUMBER NOT NULL )
CREATE TABLE OPERATION_TYPE
( ID_OPERATION NUMBER NOT NULL,
OPERATION_TYPE VARCHAR2(1) NOT NULL,
VALUE NUMBER NOT NULL)

Answer 1

I guess that it is a calendar you need, i.e. a table which contains all dates involved. Otherwise, how can you display something that doesn't exist?
This is what you currently have (I'm using only the operation table; add another one yourself):
SQL> with
2 operation (id_operation, date_operation, value) as
3 (select 1, date '2019-06-01', 100 from dual union all
4 select 2, date '2019-06-01', 200 from dual union all
5 -- 02/06/2019 is missing
6 select 3, date '2019-06-03', 300 from dual union all
7 select 4, date '2019-06-04', 400 from dual
8 )
9 select o.date_operation,
10 count(o.id_operation)
11 from operation o
12 group by o.date_operation
13 order by o.date_operation;
DATE_OPERA COUNT(O.ID_OPERATION)
---------- ---------------------
01/06/2019 2
03/06/2019 1
04/06/2019 1
SQL>
As there are no rows that belong to 02/06/2019, query can't return anything (you already know that).
Therefore, add a calendar. If you already have that table, fine - use it. If not, create one. It is a hierarchical query which adds level to a certain date. I'm using 01/06/2019 as the starting point, creating 5 days (note the connect by clause).
SQL> with
2 operation (id_operation, date_operation, value) as
3 (select 1, date '2019-06-01', 100 from dual union all
4 select 2, date '2019-06-01', 200 from dual union all
5 -- 02/06/2019 is missing
6 select 3, date '2019-06-03', 300 from dual union all
7 select 4, date '2019-06-04', 400 from dual
8 ),
9 dates (datum) as --> this is a calendar
10 (select date '2019-06-01' + level - 1
11 from dual
12 connect by level <= 5
13 )
14 select d.datum,
15 count(o.id_operation)
16 from operation o full outer join dates d on d.datum = o.date_operation
17 group by d.datum
18 order by d.datum;
DATUM COUNT(O.ID_OPERATION)
---------- ---------------------
01/06/2019 2
02/06/2019 0 --> missing in source table
03/06/2019 1
04/06/2019 1
05/06/2019 0 --> missing in source table
SQL>
Probably a better option is to dynamically create a calendar so that it doesn't depend on any hardcoded values, but uses the min(date_operation) to max(date_operation) time span. Here we go:
SQL> with
2 operation (id_operation, date_operation, value) as
3 (select 1, date '2019-06-01', 100 from dual union all
4 select 2, date '2019-06-01', 200 from dual union all
5 -- 02/06/2019 is missing
6 select 3, date '2019-06-03', 300 from dual union all
7 select 4, date '2019-06-04', 400 from dual
8 ),
9 dates (datum) as --> this is a calendar
10 (select x.min_datum + level - 1
11 from (select min(o.date_operation) min_datum,
12 max(o.date_operation) max_datum
13 from operation o
14 ) x
15 connect by level <= x.max_datum - x.min_datum + 1
16 )
17 select d.datum,
18 count(o.id_operation)
19 from operation o full outer join dates d on d.datum = o.date_operation
20 group by d.datum
21 order by d.datum;
DATUM COUNT(O.ID_OPERATION)
---------- ---------------------
01/06/2019 2
02/06/2019 0 --> missing in source table
03/06/2019 1
04/06/2019 1
SQL>