MySQL 8.0

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select version();

version()

8.0.36

CREATE TABLE `hash_list` (
  `id` bigint NOT NULL AUTO_INCREMENT,
  `hash` varbinary(45),
  PRIMARY KEY (`hash`),
  UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB
show create table hash_list;

Table
Create Table

hash_list
CREATE TABLE `hash_list` (
  `id` bigint NOT NULL AUTO_INCREMENT,
  `hash` varbinary(45) NOT NULL,
  PRIMARY KEY (`hash`),
  UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci

insert ignore into hash_list(hash) values ('bob')
select row_count(),last_insert_id();

row_count()
last_insert_id()

1
1

insert ignore into hash_list(hash)  values ('bob')
select row_count(),last_insert_id();

row_count()
last_insert_id()

0
1