ISBLANK vs ISNULL?

Question:
What are the differences between ISBLANK
and ISNULL
in Salesforce? While ISNULL
is said to work on text fields, are there specific use cases for each? Which one should be used in formulas and Apex?
Answer:
The distinction between ISBLANK
and ISNULL
depends on where they are used and the context:
In formulas, ISBLANK
and ISNULL
serve similar purposes, but there is a key difference. Salesforce recommends using ISBLANK
for new formulas because it supports text fields in addition to other types, while ISNULL
does not. Here is what the Salesforce documentation states:
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ISNULL(expression)
checks if an expression evaluates tonull
. However, it does not work reliably with text fields. When used on a text field, it always returnsfalse
, even if the field is empty.ISBLANK(expression)
behaves likeISNULL
, but it also works on text fields, correctly identifying them as blank when they are empty. Salesforce encourages usingISBLANK
for new formulas for this reason.
If you are working in Apex, ISBLANK
and ISNULL
are not directly used. Instead, you would typically rely on the String
class methods or collection methods:
String.isBlank(String input)
: Returnstrue
if the string isnull
, empty (''
), or contains only whitespace.String.isEmpty(String input)
: Returnstrue
if the string isnull
or empty, but not if it contains only whitespace.- For collections (lists, sets, maps): Use
isEmpty()
to check if they contain zero elements.
For example, in Apex:
String textValue = '';
System.debug(String.isBlank(textValue)); // true (empty or whitespace)
System.debug(String.isEmpty(textValue)); // true (empty but not whitespace)
System.debug(String.isBlank(null)); // true
System.debug(String.isEmpty(null)); // true
List<String> items = new List<String>();
System.debug(items.isEmpty()); // true
Code explanation:
The code demonstrates the behavior of String.isBlank
and String.isEmpty
methods in Apex. isBlank
returns true
if a string is null
, empty, or contains only whitespace, while isEmpty
returns true
for null
or empty strings but not for whitespace-only strings. The isEmpty
method on a collection like List
checks if it has zero elements, returning true
when the list is empty.
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