Query MySQL database to echo highest auto incremented number?

Let us first create a table with Id as auto_increment −

mysql> create table DemoTable
(
   UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   UserName varchar(20)
);
Query OK, 0 rows affected (0.56 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable(UserName) values('John');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable(UserName) values('Larry');
Query OK, 1 row affected (0.35 sec)
mysql> insert into DemoTable(UserName) values('Chris');
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable(UserName) values('Bob');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable(UserName) values('Carol');
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable(UserName) values('David');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable(UserName) values('Robert');
Query OK, 1 row affected (0.20 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 −

+--------+----------+
| UserId | UserName |
+--------+----------+
| 1      | John     |
| 2      | Larry    |
| 3      | Chris    |
| 4      | Bob      |
| 5      | Carol    |
| 6      | David    |
| 7      | Robert   |
+--------+----------+
7 rows in set (0.00 sec)

Here is the query to echo highest auto incremented number −

mysql> select *from DemoTable order by UserId desc limit 0,1;

This will produce the following output displaying the highest auto incremented value −

+--------+----------+
| UserId | UserName |
+--------+----------+
| 7      | Robert   |
+--------+----------+
1 row in set (0.00 sec)