Create table from many tables with specific data - sql

Question

We have oracle11g.
I need to write stored procedure (or may be another solution like creating view) that will truncute old table and insert new updated data.
We have many tables in database with name %table_name%+number_prefix.
For example: Country_1, Country_2.
Here is data from this tables:
id code country
103858 834 TZ
103878 834 UA
103859 800 UG
103860 894 ZM
103861 716 ZW
103862 24 AO
Also we have table Country_all, with specific information from all this tables.
If users add new table from web gui new Country_%prefix% table, i have to update Country_all table. This table should group by code and put all country in one row (TZ, UA, UG ...):
table code countries
91 2005202000 ,AD,AL,AQ,AS,AT,
91 2005400000 ,AD,AL,AQ,AS,AT,
91 2005995000 ,AD,AL,AQ,AS,AT,
91 2005997000 ,AD,AL,AQ,AS,AT,
91 2006003100 ,AD,AL,AQ,AS,AT,
Here 91 means that this data from table Country_91
I use this to get prefix from table:
EXECUTE IMMEDIATE 'truncate table COUNTRY_ALL';
FOR r IN (SELECT regexp_replace(table_name,'(.*)_', '\1') ADD_NUM
FROM all_tables
WHERE upper(table_name)
LIKE ('COUNTRY_%'))
But when i try to use r.ADD_NUM i have trouble.
INSERT INTO COUNTRY_ALL
SELECT r.ADD_NUM, code, listagg(code, ',') WITHIN GROUP (ORDER BY code) AS GI_COUNTRIES
FROM 'COUNTRY_' || r.ADD_NUM
GROUP BY code;
I also try to declare some variable and assign COUNTRY_ || r.ADD_NUM to the variable, but it also don't want to query from variable.
UPDATE
Finally i did it yesterday!
I did it in two ways. The first one is exactly what i was asking:
BEGIN
EXECUTE IMMEDIATE 'truncate table Countries_ALL';
FOR r IN (SELECT regexp_replace(table_name,'_(.*)', '\1') ADD_NUM
FROM all_tables
WHERE upper(table_name)
LIKE ('COUNTRY_%')
AND owner='owner_name')
loop
EXECUTE IMMEDIATE 'INSERT COUNTRIES_ALL
SELECT '|| r.ADD_NUM ||' as ADD_NUM, code, listagg(countries, '','') WITHIN GROUP (ORDER BY countries) AS COUNTRIES
FROM COUNTRY_' || r.ADD_NUM || '
GROUP by code;
END loop;
END;
The second one is better. I create 2 temporary tables: CURRENT and FOR_UPDATING.
To fill CURRENT:
INSERT INTO CURRENT
SELECT DISTINCT ADD_NUM FROM COUNTRIES_ALL;
And procedure that will update only not existing table, unlike previous one:
DECLARE
BEGIN
execute IMMEDIATE 'TRUNCATE table for_updating';
INSERT INTO for_updating
SELECT regexp_replace(table_name,'_(.*)', '\5 ') as ADD_NUM
FROM all_tables
WHERE owner='owner_name'
AND table_name LIKE 'COUNTRY_%';
for num in (
SELECT b.add_num FROM CURRENT A
RIGHT JOIN for_updating b
ON A.add_num=b.add_num
WHERE A.add_num IS NULL)
loop
EXECUTE IMMEDIATE 'INSERT INTO COUNTRIES_ALL
SELECT '||num.add_num||' as ADD_NUM, code, listagg(countries, '','') WITHIN GROUP (ORDER BY countries) AS GI_COUNTRIES
FROM COUNTRY_' || num.ADD_NUM || '
GROUP by code';
end loop;
END;
In this procedure i compare what tables i already have in COUNTRIES_ALL and what i have in all_tables. Then all new tables will be inserted.
Thanks to Przemyslaw Kruglej for his patience!

Answer 1

You can't run a query with dynamic name of the table.
You have to either generate a query for each of the tables, use dbms_sql package or EXECUTE IMMEDIATE.
Do you know the number of the table you are supposed to work on? If so, you can use EXECUTE IMMEDIATE:
EXECUTE IMMEDIATE
'INSERT INTO COUNTRY_ALL
SELECT r.ADD_NUM, code, listagg(code, '','') WITHIN GROUP (ORDER BY code) AS GI_COUNTRIES
FROM COUNTRY_' || tab_number ||
' GROUP BY code';