Get Max ID from Varchar Type in MySQL

Use CAST() in MAX() to get max id from varchar type and values in numeric. Let us first create a table. Here, we have a column with varchar type −

mysql> create table DemoTable
(
   UserMarks varchar(20)
);
Query OK, 0 rows affected (0.77 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values('77');
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable values('98');
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable values('45');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable values('56');
Query OK, 1 row affected (0.18 sec)
mysql> insert into DemoTable values('89');
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable values('99');
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable values('91');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable values('94');
Query OK, 1 row affected (0.15 sec)

Following is the query to display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the Following output −

+-----------+
| UserMarks |
+-----------+
| 77        |
| 98        |
| 45        |
| 56        |
| 89        |
| 99        |
| 91        |
| 94        |
+-----------+
8 rows in set (0.00 sec)

Following is the query to get max id from varchar type and the values in numeric −

mysql> SELECT MAX(CAST(UserMarks AS SIGNED)) AS MAX_VALUE from DemoTable;

This will produce the Following output −

+-----------+
| MAX_VALUE |
+-----------+
| 99        |
+-----------+
1 row in set (0.00 sec)