Postgres 17

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create table t (a varchar(30) not null, b varchar(30) not null);

CREATE TABLE

insert into t
  VALUES ('John', 'Test'),
  ('VWXYZVWXYZVWXYZVWXYZVWXYZVWXYZA', 'Some Name')
;

ERROR:  value too long for type character varying(30)

INSERT INTO t
SELECT *
FROM UNNEST(
  ('{Jane,ABCDEABCDEABCDEABCDEABCDEABCDEX}')::varchar(30)[],
  ('{Doe,"Doesnt Matter"}')::varchar(30)[]
);

INSERT 0 2

select * from t;

a
b

Jane
Doe

ABCDEABCDEABCDEABCDEABCDEABCDE
Doesnt Matter

SELECT 2

SELECT 'ABCDEABCDEABCDEABCDEABCDEABCDEX'::varchar(30);

varchar

ABCDEABCDEABCDEABCDEABCDEABCDE

SELECT 1