Writing a PLSQL select in array - sql

Question

I'm using a DB 'A' to output a list of numbers :
123455
123456
123457
And I'm looking to build a dynamic statement to look into a DB 'B' with those results as a filter
a. Build an array with the values from DB 'A'
SELECT * FROM my_table
WHERE number in &array;
How can I achieve this ?
The DB 'B' is an Oracle DB.
Thanks

Answer 1

Hm. Looks like your "background" is not Oracle, because there are no "DB"s there. I mean, there are, but not in a context you're using them. If "DB" stands for a "Database", to me it looks as if you're actually talking about tables here.
Also, I don't understand what
The DB 'B' is in PLSQL means.
If "database" is a table, how is it in PL/SQL?
Anyway, to get you started: I'm fetching some data from Scott's EMP and DEPT tables. For collections, I'm using Oracle's built-in types.
These are employees in departments 10 and 20:
SQL> select deptno, ename
2 from emp
3 where deptno in (10, 20)
4 order by deptno, ename;
DEPTNO ENAME
---------- ----------
10 CLARK
10 KING
10 MILLER
20 ADAMS
20 FORD
20 JONES
20 SCOTT
20 SMITH
8 rows selected.
PL/SQL procedure which does something with them (the way I understood the question):
SQL> declare
2 l_a sys.odcinumberlist;
3 l_b sys.odcivarchar2list;
4 begin
5 select deptno
6 bulk collect into l_a
7 from dept
8 where deptno in (10, 20);
9
10 select ename
11 bulk collect into l_b
12 from emp
13 where deptno in (select * from table(l_a))
14 order by ename;
15
16 for i in l_b.first .. l_b.last loop
17 dbms_output.put_line(l_b(i));
18 end loop;
19 end;
20 /
ADAMS
CLARK
FORD
JONES
KING
MILLER
SCOTT
SMITH
PL/SQL procedure successfully completed.
SQL>
Lines #1 - 3 - declaration section
lines #5 - 8 - inserting values (departments) into l_a collection
Lines #10 - 14 - inserting values (employees) into l_b collection, based on values stored in l_a
Lines #16 - 18 - displaying contents of l_b
See if it helps.
[EDIT] After seeing your comment: as far as I can tell, you can't do what you wanted, not as simple as you'd want it to. This is how it works - you enter a comma-separated values as a parameter (that's your "array"), split it into rows and use the result as a subquery:
SQL> SELECT *
2 FROM dept
3 WHERE deptno IN ( SELECT REGEXP_SUBSTR ( '&&par_depts',
4 '[^,]+',
5 1,
6 LEVEL)
7 FROM DUAL
8 CONNECT BY LEVEL <= REGEXP_COUNT ( '&&par_depts', ',') + 1);
Enter value for par_depts: 10,20
DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
SQL>
This is a SQL*Plus example; you'll probably have to substitute '&&par_depts' with :par_depts (depending on a tool you use).

Answer 2

Use the MEMBER operator.
First create a collection type in SQL:
CREATE TYPE int_list IS TABLE OF INT;
Then just use it in an SQL statement:
SELECT *
FROM my_table
WHERE value MEMBER OF int_list(123455, 123456, 123457);
Which, for the sample data:
CREATE TABLE my_table ( id, value ) AS
SELECT LEVEL, 123453 + LEVEL FROM DUAL CONNECT BY LEVEL <= 5;
Outputs:
ID
VALUE
2
123455
3
123456
4
123457
If you want it in PL/SQL then:
DECLARE
items int_list := int_list(123455, 123456, 123457);
BEGIN
FOR row IN (
SELECT *
FROM my_table
WHERE value MEMBER OF items
)
LOOP
DBMS_OUTPUT.PUT_LINE( row.id || ', ' || row.value );
END LOOP;
END;
/
Which, for the same data, outputs:
2, 123455
3, 123456
4, 123457
db<>fiddle here
However, if you just want to connect two databases then setup a database link.