How to use a variable as a table name in PL/SQL?

Question

Hello all.
I was given one day to wrote a piece of PL/SQL code to do a query. That is,
First select two columns from one table and use them to build another table's name, then
     join the two tables. I'm not sure if variables can be used in the select list, if possible,
     how to reference them?
-- My code is
DECLARE
     tablename varchar2(40);
     CURSOR c1 IS
select a.sourcesystemcode, a.adminorganizationno from cdb1.organization_mapping a
where exists( select 1 from cdb1.organization_mapping b where
a.cdborganizationno = b.cdborganizationno and a.adminorganizationno != b.adminorganizationno)
order by a.cdborganizationno,a.adminorganizationno;
     v_src_sys_cod cdb1.organization_mapping.sourcesystemcode%TYPE;
     v_adm_org_no cdb1.organization_mapping.adminorganizationno%TYPE;
BEGIN
OPEN c1;
LOOP
FETCH c1 INTO v_src_sys_cod, v_adm_org_no;
EXIT WHEN c1%NOTFOUND;
tablename := 'ODS1.SRC_' || v_src_sys_cod || v_adm_org_no || 'ACTORG_CURR';
select c.cdborganizationno, c.sourcesystemcode, c.adminorganizationno, c.sourceorganizationno, d.ibkcde, d.orgnam
from cdb1.organization_mapping c inner join tablename d on c.sourceorganizationno = d.orgidt;
END LOOP;
CLOSE c1;
END;
The error message says "... the table or view does not exist... line 18, column 66..."
It says the variable "tablename" wasn't build or build incorrectly.
Please give the solution.

Answer 1

If the TABLEs being queried are already known, and it is just a matter of which one to query, perhaps you can CREATE a VIEW that uses all the TABLEs with a UNION ALL, and include an identifier COLUMN.
CREATE VIEW SRC_ALL_ACTORG_CURR
AS
SELECT 'aa' Name, ibkcde, orgnam FROM SRC_aa_ACTORG_CURR UNION ALL
SELECT 'bb' Name, ibkcde, orgnam FROM SRC_bb_ACTORG_CURR UNION ALL
SELECT 'cc' Name, ibkcde, orgnam FROM SRC_cc_ACTORG_CURR UNION ALL
SELECT 'dd' Name, ibkcde, orgnam FROM SRC_dd_ACTORG_CURR UNION ALL
SELECT 'ee' Name, ibkcde, orgnam FROM SRC_ee_ACTORG_CURR;
Then, in you query:
select c.cdborganizationno, c.sourcesystemcode, c.adminorganizationno, c.sourceorganizationno, d.ibkcde, d.orgnam
from cdb1.organization_mapping c inner join SRC_ALL_ACTORG_CURR d on c.sourceorganizationno = d.orgidt and d.Name = v_src_sys_cod || v_adm_org_no;