SQL NULL Vs EMPTY Statement
The major distinction between
NULL refers to nothing, whereas
EMPTY refers to a single string of zero length.
A string is a collection of characters. "Programming," for example, is a String .
Strings are supported by the Java programming language and are considered as objects.
String class is unchangeable.
As a result, once an item is created, it cannot be modified.
Strings can be null or empty at times.
When you assign null to a
String variable, it means the variable isn't actually referring to any memory location in the heap.
The assignment of an empty
String to a
String variable, on the other hand, implies that the reference variable is pointing to a memory address of a
String of zero length .
SQL NULL Statement
Nothing is referred to as null. NULL indicates that we have no idea what the value is; it may or may not exist; we just don't know. Take note of the following two statements.
s1 is a
String. It's been given the value of null. As a result, the JVM will
s1 will be null.
String s1 = null;
this is also equivalent to
String s1; When printing function does not count the length of a string.
Example: Let's start by looking at an example that shows how to use the
IS NULL condition in a
In this example, we have a table called
Country with the following data:
Enter the following SQL statement://Mysql,Sql-server,Sqlite,Ms access
SELECT * FROM Country WHERE Continent IS NULL;
When testing for a NULL value,
IS NULL is the recommended comparison operator to use in SQL. There will be 1 record selected.
Output: This example will return all records from the Country table where the Continent contains a
Empty-String denotes that we are aware of the value and that it is zero. The term "empty" refers to a string that has no length. Please see the code below.
s2 is a
String. It is given the value "" as an empty string.
As a result, the JVM will set aside memory for an empty string. That empty string will be referred to by
It will print 0 when the length of the
String s2 is printed.
This is because
s1 refers to a
String, but there are no characters in it to count the length.
SQL DIFFERENCE BETWEEN NULL AND EMPTY FUNCTION
In below table we will discusse the distinguish between null & empty function:-
|Column 1||Column 2|
|NULL is a phrase used to denote that an object refers to nothing on the heap.||EMPTY is a word that denotes that an object refers to a single zero-length string in the heap.|
|A null pointer exception will be thrown if the length of the null string is printed.||If you print the length of an empty string, you'll get a zero.|
|Null can refer to an unknown value or a value that does not exist.||An empty or blank string is a value that is just that: it is empty.|
|Null can be used to represent a string, an integer, a date, or any other field in a database.||For string fields, the value empty is used.|
|Because NULL is an unknown value, no memory is allocated to a field with NULL.||EMPTY fields have no value and are assigned memory space.|
|If you don't allow empty strings but don't require the user to enter a value, NULL is a good option.||If you need a value but it can be empty,