- 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
How to order DESC by a field, but list the NULL values first?
To order by a field and list the NULL values first, you need to use the following syntax. This will order in descending order −
select yourColumnName from yourTableName group by yourColumnName is null desc,yourColumnName desc;
To understand the above syntax, let us first create a table −
mysql> create table OrderByNullFirstDemo −> ( −> StudentId int −> ); Query OK, 0 rows affected (0.56 sec)
Insert some records in the table with the help of insert command. The query is as follows −
mysql> insert into OrderByNullFirstDemo values(100); Query OK, 1 row affected (0.13 sec) mysql> insert into OrderByNullFirstDemo values(200); Query OK, 1 row affected (0.13 sec) mysql> insert into OrderByNullFirstDemo values(150); Query OK, 1 row affected (0.13 sec) mysql> insert into OrderByNullFirstDemo values(NULL); Query OK, 1 row affected (0.15 sec)
Display all records from the table with the help of select statement. The query to display all records is as follows −
mysql> select *from OrderByNullFirstDemo;
The following is the output −
+-----------+ | StudentId | +-----------+ | 100 | | 200 | | 150 | | NULL | +-----------+ 4 rows in set (0.00 sec)
Implement the syntax we discussed in the beginning to perform order in descending order and display the null valu efirst −
mysql> select StudentId from OrderByNullFirstDemo group by StudentId is null desc,StudentId desc;
The following is the output −
+-----------+ | StudentId | +-----------+ | NULL | | 200 | | 150 | | 100 | +-----------+ 4 rows in set, 2 warnings (0.00 sec)
Advertisements