When having a check constraint on a virtual column, the column in question must be present in any insert statement and have a value that fulfills the check constraint, despite this value being overwritten by the virtual column formula later, like this:

CREATE TABLE tv1(c1 int, c2 int as (c1 + 1), CHECK (c2 > 2));

The following fails, which is correct (c2 is 2 which is wrong):

INSERT INTO tv1(c1) VALUES(1);

But the following also fails:

INSERT INTO tv1(c1) VALUES(2);

The following also fails (again as c2 is 2):

INSERT INTO tv1 VALUES(1,NULL);

But the following works:

INSERT INTO tv1 VALUES(2,NULL);

Which you would think is the same as:

INSERT INTO tv1(c1) VALUES(2);

But as shown above it is not