Select and insert values with preceding zeros in a MySQL table

For this, you can use INSERT INTO SELECT statement along with LPAD(). Let us first create a table −

mysql> create table DemoTable1967
   (
   Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   UserId varchar(20)
   );
Query OK, 0 rows affected (0.00 sec)

Insert some records in the table using insert command −

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

Display all records from the table using select statement −

mysql> select * from DemoTable1967;

This will produce the following output −

+----+--------+
| Id | UserId |
+----+--------+
|  1 | 001    |
|  2 | 002    |
|  3 | 003    |
+----+--------+
3 rows in set (0.00 sec)