Why it shows 0 instead of empty string whenever I insert an empty string into a MySQL column which is declared as NOT NULL?

It is because inserting an empty string means that we are inserting some value and not NULL. The empty string apparently maps to zero as an integer. In other words, we can say that by inserting empty string we are providing a value to MySQL that has integer representation as INT 0. Consider the following example in which we inserted an empty string and it mapped to 0 by MySQL.

mysql> create table test(id int NOT NULL, Name Varchar(10));
Query OK, 0 rows affected (0.19 sec)

mysql> Insert into test(id, name) values('1', 'Gaurav'),('0','Rahul'),('','Aarav');
Query OK, 3 rows affected, 1 warning (0.08 sec)
Records: 3 Duplicates: 0 Warnings: 1

mysql> Select * from test;
+----+--------+
| id | Name   |
+----+--------+
| 1  | Gaurav |
| 0  | Rahul  |
| 0  | Aarav  |
+----+--------+
3 rows in set (0.00 sec)

Rishi Rathor

Published on 22-Feb-2018 06:31:55

• Related Questions & Answers
• What role data type plays when I insert an empty string into a MySQL column which is declared as NOT NULL?
• How it is possible to insert a zero or an empty string into a MySQL column which is defined as NOT NULL?
• Empty string in not-null column in MySQL?
• Which one is better to insert NULL or empty string in MySQL?
• Which one is better in MySQL - NULL or empty string?
• Check if a String is not empty ("") and not null in Java
• Insert default into not null column if value is null in MySQL?
• How to test String is null or empty?
• How do I check if a column is empty or null in MySQL?
• How to update empty string to NULL in MySQL?
• Split a string and insert it as individual values into a MySQL table?
• MongoDB query which represents not equal to null or empty?
• Why is the size of an empty class not zero in C++?
• Java Program to check if a string is empty or not
• Check if a String is empty ("") or null in Java