Postgres 15

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CREATE TABLE tbl (
  int1    int
, int2    int
, product bigint GENERATED ALWAYS AS (int1 * int2) STORED
);

CREATE TABLE


INSERT INTO tbl(int1, int2)
VALUES
  (3, 4)
, (5, -6)
, (7, NULL);

INSERT 0 3


TABLE tbl;


int1
int2
product


3
4
12

5
-6
-30

7
null
null



SELECT 3