Introduction to filter expressions

Filter expressions are integrated into various parts of the BizzStream platform to provide granular control over data visibility and relationships. Here's a detailed look at where you'll encounter them and how to apply them.

Filter Expressions

Filter expressions are SQL-like conditions that are used to filter documents. In filter expressions, you can incorporate text expressions by enclosing them in double curly braces ({{ }}). For example, the following filter expression selects documents where the "price" field is greater than 0 and less than a value set in the "maximumValue" field.

price > 0 AND price < {{F["maximumValue"]}}

Note that filter expressions support only a limited subset of SQL operators and keywords.

Where Are Filter Expressions Used?

They will be all explained further in their own individual documentation. A quick preview of what each expression is used for is described here:

Location	Purpose	Description
Document definitions	Reference Filter	Defines filters for reference fields.
Layouts	Dataset Filter	Applies a filter to a dataset.
Menus	Menu Block Filter	This is a crucial point in the dataset filters in these menu blocks. Can filter a document out of a whole dataset.

Filter Comparison Operators

Operator	Description	Usage/Example
= or IS	Checks if values are equal.	{{F['price']}} IS 5
<> or != or IS NOT	Checks if values are not equal.	{{F['price']}} IS NOT 5
>	Checks if a value is greater than another.	{{F['price']}} > 5
<	Checks if a value is less than another.	{{F['price']}} < 5
>=	Checks if a value is greater than or equal to another.	{{F['price']}} >= 5
<=	Checks if a value is less than or equal to another.	{{F['price']}} <= 5
BETWEEN	Checks if a value falls within a given range.	{{F['price']}} BETWEEN 1 AND 10
IN	Checks if a value exists within a list.	{{F['price']}} IN [5, 4, 3]
NOT IN	Checks if a value does not exist within a list.	{{F['price']}} NOT IN [4, 3]
CONTAINS	Checks if a field contains a specific substring.	CONTAINS({{F['name']}}, 'Duit 8')
NOT CONTAINS	Checks if a field does not contain a specific substring.	NOT CONTAINS({{F['name']}}, 'Duit 8')
ISBLANK	Checks if a field has no value (null, empty string, empty array, or missing).	ISBLANK(fieldName)
NOT ISBLANK	Checks if a field has any value.	NOT ISBLANK(fieldName)

These operators can also be used in combination with BizzStream Expressions. The linked documentation offers essential insight into filter usage and the flexibility they support.

Chaining Operators

Operator	Description
AND	Returns documents where all specified conditions are TRUE.
OR	Returns documents where at least one condition is TRUE.

These operators allow you to chain filter comparison operators. For example:

number >= 5 AND number IS NOT 10

This ensures that number, which can be changed per use case, is greater than or equal to 5 and is not 10.

Logical Operators

Operator	Description
IF	Enables a picking between two filter conditions based on a condition.

IF({{F["price"] > 5}}, {{URLRESOLVER("filter")}}, date = {{TODAY()}})

If condition ({{F["price"] > 5}} resolves to a truthy value, then {{URLRESOLVER("filter")}} will be used, other wise the date = {{TODAY()}} filter will be used

Empty Field Operators

The ISBLANK and NOT ISBLANK operators let you filter documents based on whether a field has a value or not. They do not require a comparison value.

Operator	Returns documents where…
ISBLANK	The field is null, "" (empty string), [] (empty array), or missing.
NOT ISBLANK	The field has any value (including 0, false, or non-empty strings).

Syntax

ISBLANK(fieldName)
NOT ISBLANK(fieldName)

Examples

ISBLANK(email)

Returns all documents where the email field is empty, null, or missing.

NOT ISBLANK(email)

Returns all documents where the email field contains a non-empty value.

NOT ISBLANK(email) AND 'country' = "NL"

Returns documents where email has a value and country equals "NL".

Getting started

To start using these filters, begin by reading about the different types listed in the table above. After that, you can explore the various expression filters.