選擇並在 MySQL 表中插入帶前導零的值
為此,可以使用 INSERT INTO SELECT 語句和 LPAD()。我們首先建立一個表 -
mysql> create table DemoTable1967 ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserId varchar(20) ); Query OK, 0 rows affected (0.00 sec)
使用 insert 命令在表中插入一些記錄 -
mysql> insert into DemoTable1967(UserId) select LPAD(COALESCE(MAX(id), 0) + 1, 3, '0') from DemoTable1967; Query OK, 1 row affected (0.00 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> insert into DemoTable1967(UserId) select LPAD(COALESCE(MAX(id), 0) + 1, 3, '0') from DemoTable1967; Query OK, 1 row affected (0.00 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> insert into DemoTable1967(UserId) select LPAD(COALESCE(MAX(id), 0) + 1, 3, '0') from DemoTable1967; Query OK, 1 row affected (0.00 sec) Records: 1 Duplicates: 0 Warnings: 0
使用 select 語句顯示錶中的所有記錄 -
mysql> select * from DemoTable1967;
這將產生以下輸出 -
+----+--------+ | Id | UserId | +----+--------+ | 1 | 001 | | 2 | 002 | | 3 | 003 | +----+--------+ 3 rows in set (0.00 sec)
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