SQL & PL/SQL

Hello Experts, (I appologize if i am not using the right way to ask questions)

I have a database, and it has around 400 schemas in it. I have designed a query which will fetch the data from three different table's from Schema1.
But it will be a tedious process of entering the 400 schemas names and pulling the information.

I would like to know as to what would be the best possible way to;
1) Look for all the schemas in the database
2) Look for those specific tables in the schema, which has the data in the tables.
3) If the tables are not present, than Ignore that schema and proceed further.
4) Load the data into a table

Any help, would appreciate it.

Thanks!


The query that i am using is as follows;

-- Query to select all the Schemas from the database
select username from all_users
order by username;

-- Sample Query to see if Tables exsist in the schema
SELECT DISTINCT OWNER, OBJECT_NAME
FROM ALL_OBJECTS
WHERE OBJECT_TYPE = 'TABLE'
AND OBJECT_NAME IN ('ENROLLMENT', 'PRDCT', 'L_P_L')
AND OWNER in ('Schema_1', 'Schema_2', Schema_3', Schema_4',Schema_5', Schema_6')
ORDER BY OWNER;


--Query to get the data from the tables in a Schema
select 'Schema_1@DATABASE_NAME' AS SCHEMA,
(SELECT MAX(LOAD_DT) FROM Schema_1.LOAD_STATUS) AS MAX_LOAD,
L_PROD_LINE.PROD_LINE,
COUNT(DISTINCT ENROLLMENT.MEM_NBR) AS MEMBERSHIP
FROM
Schema_1.ENROLLMENT,
Schema_1.PRDCT,
Schema_1.L_P_L
WHERE
ENROLLMENT.PRODUCT_ID = PRDCT.PRODUCT_ID AND
PRODUCT.PROD_LINE_ID = L_P_L.ID
GROUP BY
L_P_L.PROD_LINE;