how to get the difference between 2 tables in 2 different schema's in Oracle? [duplicate]

Question

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Comparing values between two tables (3 answers)

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I am using Oracle 11G.

I have a table called Tickets in the schema called 'tickets1" I have the same table structure in another schema called 'tickets2'

I want to find out

1. What data is the same in both tables?
2. What data is different?

CREATE TABLE tickets(
    ticket_number NUMBER NOT NULL,    
    first_name VARCHAR2(50) NOT NULL,
    last_name VARCHAR2(50) NOT NULL,
    PRIMARY KEY(ticket_number)
);

Answer 1

To mustaccio's point, there's nothing particular about a schema that prevents you from querying objects from different schemas within the same query (putting privileges aside - since that's a function of security, not a unique feature of schemas).

So you can use a FULL JOIN between the two tables across schemas with an appropriate WHERE clause like so to answer your questions:

-- Gets all rows that have the same primary key (ticket_number) between the two tables
SELECT * -- Replace * with only the columns you need, as using * is generally bad practice
FROM tickets1.Tickets T1
FULL JOIN tickets2.Tickets T2
    ON T1.ticket_number = t2.ticket_number
WHERE T1.ticket_number IS NOT NULL
    AND T2.ticket_number IS NOT NULL

-- Gets all rows that have different primary keys (ticket_number) between the two tables
SELECT * -- Replace * with only the columns you need, as using * is generally bad practice
FROM tickets1.Tickets T1
FULL JOIN tickets2.Tickets T2
    ON T1.ticket_number = t2.ticket_number
WHERE (T1.ticket_number IS NOT NULL AND T2.ticket_number IS NULL)
    OR  (T1.ticket_number IS NULL AND T2.ticket_number IS NOT NULL)

Note the above only compares the two tables by the primary key (ticket_number). Depending on your definition of "same data" / "different data", you may want to compare by other fields in the tables as well.