Postgres 18

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create table franck ( val int unique );

CREATE TABLE

insert into franck values (1),(2),(3),(4),(5);

INSERT 0 5

update franck set val=val+1;

ERROR:  duplicate key value violates unique constraint "franck_val_key"
DETAIL:  Key (val)=(2) already exists.

update franck set val=val+1 where val<3;

ERROR:  duplicate key value violates unique constraint "franck_val_key"
DETAIL:  Key (val)=(2) already exists.