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
What MySQL would return if we refer a user variable which is not assigned any value explicitly?
In case, when we refer a user variable which is not assigned any value explicitly, MySQL would return NULL. In other words, its value would be NULL. Following example would illustrate it −
mysql> Select @X, @Y, @Z, @S, @G; +------+-------+----------+------+------+ | @X | @Y | @Z | @S | @G | +------+-------+----------+------+------+ | Ram | Shyam | Students | 5000 | NULL | +------+-------+----------+------+------+ 1 row in set (0.00 sec)
We can see from the above result set that @X,@Y,@Z and @S has been assigned values explicitly and they returned the values but @G variable has not been assigned any value explicitly hence when we refer to it then MySQL returns NULL because it is having a NULL value.
Updated on: 20-Jun-2020
59 Views
Advertisements