- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Does using SERIAL as column name already includes 'NOT NULL' in MySQL?
In MySQL, SERIAL is an alias for BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE. So, do not use NOT NULL after SERIAL, since it already includes NOT NULL as part of its definition.
Let us see an example and create a table. Here, we have a column with the name “serial” −
mysql> create table DemoTable ( Id serial ); Query OK, 0 rows affected (0.42 sec)
Insert some records in the table using insert command. We aren’t including any value while inserting −
mysql> insert into DemoTable values(); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable values(); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(); Query OK, 1 row affected (0.06 sec) mysql> insert into DemoTable values(); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(); Query OK, 1 row affected (0.07 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+----+ | Id | +----+ | 1 | | 2 | | 3 | | 4 | | 5 | | 6 | +----+ 6 rows in set (0.00 sec)
Advertisements