Question

So lets say I have TABLE1 and TABLE2.

CREATE TABLE TABLE1
(
first_id int NOT NULL,
first_random_attribute varchar(255)
primary key(first_id)
)

CREATE TABLE TABLE2
(
second_id int NOT NULL,
second_random_attribute varchar(255)
primary key(second_id)
)

How would a compare TABLE1 and TABLE2 with one another, create a relational table, check if their x_random_attribute’s are equivalent and if they are, store the primary keys of each one in the new relational table?

Answer 1

Portable SQL

CREATE TABLE Whatever (
  first_id int NOT NULL,
  second_id int NOT NULL,
  common_random_attribute varchar(255)
  );

INSERT Whatever (first_id, second_id, common_random_attribute)
SELECT
    t1.first_id, t2.second_id, t1.first_random_attribute
FROM
    TABLE1 t1
    JOIN
    TABLE2 t2 ON t1.first_random_attribute = t2.second_random_attribute;

Specific alternatives:

• MySQL allows you to CREATE TABLE AS SELECT ... in one statement
• SQL Server/Sybase have SELECT .. INTO ...