pivot table with two rows into columns - sql

Question

i have the next result for my table:
our_date | number_people
------------------------
23/09/19 | 26
24/09/19 | 26
ALWAYS will be just two rows
and i want pivot this result and get this:
our_date_1 | number_people_1 | our_date_2 | number_people_2
-----------------------------------------------------------------
23/09/19 | 26 | 24/09/19 | 26
to get the differences between number_people_1 and number_people_2
i try with:
select *
from table_1
pivot(
count(number_people)
for our_date in (:P_TODAY, :P_YESTERDAY)
)
and this is my actual error:
ORA-56900: la variable de enlace no está soportada en la operación PIVOT|UNPIVOT
56900. 0000 - "bind variable is not supported inside pivot|unpivot operation"
*Cause: Attempted to use bind variables inside pivot|unpivot operation.
*Action: This is not supported.
what's is wrong? how can i use dynamic values inside for clause ?
Best regards

Answer 1

Error says that this:
for fecha in (our_date)
can't have our_date (column name) as list of values; it (the list) has to contain constants, e.g.
for our_date in (date '2019-09-23', date '2019-09-24')
Once you fix that, query might look like this:
SQL> with table_1 (our_date, number_people) as
2 (select date '2019-09-23', 26 from dual union all
3 select date '2019-09-24', 26 from dual
4 )
5 select *
6 from table_1
7 pivot (max(number_people)
8 for our_date in (date '2019-09-23', date '2019-09-24')
9 );
TO_DATE(' 2019-09-23 00:00:00' TO_DATE(' 2019-09-24 00:00:00'
------------------------------ ------------------------------
26 26
SQL>
But, that's not exactly what you wanted.
What if there are 3, 4 or more rows in that table? Is it possible, or will there always be only 2 rows?
If it is always only 2 rows, self-join can do the job. For example:
SQL> with table_1 (our_date, number_people) as
2 (select date '2019-09-23', 26 from dual union all
3 select date '2019-09-24', 22 from dual
4 ),
5 temp as
6 (select our_date, number_people,
7 row_number() over (order by our_date) rn
8 from table_1
9 )
10 select
11 a.our_date our_date_1,
12 a.number_people number_people_1,
13 --
14 b.our_date our_date_2,
15 b.number_people number_people_2
16 from temp a cross join temp b
17 where a.rn = 1
18 and b.rn = 2;
OUR_DATE_1 NUMBER_PEOPLE_1 OUR_DATE_2 NUMBER_PEOPLE_2
---------- --------------- ---------- ---------------
23.09.2019 26 24.09.2019 22
SQL>