### テーブルを作る。 mysql> create table demo(id serial primary key, n integer not null); Query OK, 0 rows affected (0.02 sec) ### とりあえず3件データを挿入。 mysql> insert into demo(n) values(1); Query OK, 1 row affected (0.00 sec) mysql> insert into demo(n) values(2); Query OK, 1 row affected (0.00 sec) mysql> insert into demo(n) values(300); Query OK, 1 row affected (0.00 sec) ### 3桁 0埋め mysql> select lpad(n, 3, '0
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