Postgres 13

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CREATE TABLE table1 (ID SERIAL, ANIMAL VARCHAR(3));
INSERT INTO table1 (ANIMAL) VALUES
  ('Cat'),
  ('Dog');

CREATE TABLE table2 (ID SERIAL, FRUIT VARCHAR(10));
INSERT INTO table2 (FRUIT) VALUES
  ('apple'),
  ('orange'),
  ('banana');

CREATE TABLE table3 (ID SERIAL, ANIMAL VARCHAR(10), FRUIT VARCHAR(10));
INSERT INTO table3 (ANIMAL, FRUIT) VALUES
  ('Bird', 'mango'),
  ('Bird', 'grape');

CREATE TABLE

INSERT 0 2

CREATE TABLE

INSERT 0 3

CREATE TABLE

INSERT 0 2

INSERT INTO table3 (ANIMAL, FRUIT) 
SELECT ANIMAL, 'Dog'
FROM table1;

INSERT 0 2

SELECT * FROM table3;

id
animal
fruit

1
Bird
mango

2
Bird
grape

3
Cat
Dog

4
Dog
Dog

SELECT 4