How to insert auto_increment in an already created table in MySQL?

Use ALTER command for this. Let us first create a table −

mysql> create table DemoTable
-> (
-> StudentName varchar(100)
-> );
Query OK, 0 rows affected (0.46 sec)

Here is the query to insert auto_increment −

mysql> alter table DemoTable ADD COLUMN StudentId int NOT NULL;
Query OK, 0 rows affected (0.50 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql> alter table DemoTable ADD PRIMARY KEY(StudentId);
Query OK, 0 rows affected (1.23 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql> alter table DemoTable CHANGE StudentId StudentId int NOT NULL
AUTO_INCREMENT;
Query OK, 0 rows affected (2.20 sec)
Records: 0 Duplicates: 0 Warnings: 0

Insert some records in the table using insert command −

mysql> insert into DemoTable(StudentName) values('Chris');
Query OK, 1 row affected (0.17 sec)

mysql> insert into DemoTable(StudentName) values('David');
Query OK, 1 row affected (0.15 sec)

Display all records from the table using select statement

mysql> select *from DemoTable;

Output

This will produce the following output −

+-------------+-----------+
| StudentName | StudentId |
+-------------+-----------+
| Chris       | 1         |
| David       | 2         |
+-------------+-----------+
2 rows in set (0.00 sec)

Karthikeya Boyini

Published on 11-Jul-2019 07:41:35

• Related Questions & Answers
• How to add a column using MySQL SELECT in an already created table?
• How to create and fill a new column in an already created MySQL table?
• Create a MySQL table from already created table selecting specific rows?
• How to randomize an already created vector in R?
• MySQL INSERT INTO SELECT into a table with AUTO_INCREMENT
• How to add NOT NULL constraint to an already created MySQL column?
• Can we insert records in a MySQL table without auto_increment values?
• How to check an empty table already in a MySQL database?
• How to insert own values into auto_increment column in MySQL?
• MongoDB query to add a document in an already created collection
• How to store time created in a MySQL table?
• How to insert an array of values in a MySQL table with a single INSERT?
• Sorting an already sorted internal table in ABAP
• Concatenate a string in an already created field values set with MySQL TEXT data type
• Is there a need to insert auto_increment column values in MySQL while using INSERT statement?