Filtering Items

This topic describes the general rules for specifying properties in filters that are supported by various objects in Outlook. See the topics in the Filter Syntax section for further information on specifying conditions on properties to complete a filter.

A filter is a condition or a set of conditions that you can apply to a set of items in order to obtain a subset of items that meets the specified conditions. Outlook supports filters using the Microsoft Jet query language syntax or the DAV Searching and Locating (DASL) syntax. Note that the Jet query language syntax has the same syntax as that supported by Microsoft Jet Expression Service, hence the name Jet query language.

As an example, you can filter contact items in your Contacts folder to obtain a list of contacts residing in Canada. In this case, you will be filtering on the HomeAddressCountry property. The filter, expressed as a Jet filter, will be "[HomeAddressCountry] = 'Canada'".

Outlook provides filtering through the following entry points:

Entry Point	Jet Filter Support	DASL Filter Support
Application.AdvancedSearch	No	Yes
Folder.GetTable	Yes	Yes
Items.Find	Yes	Yes. Note that if you use the query keywords ci_phrasematch or ci_startswith in the filter, you will get an error.
Items.Restrict	Yes	Yes
Search.GetTable	No	Yes
Table.FindRow	Yes	Yes. Note that if you use the query keywords ci_phrasematch or ci_startswith in the filter, you will get an error.
Table.Restrict	Yes	Yes
View.Filter	No	Yes

Note

A filter must contain a query in either Jet or DASL syntax but not a mixture of both.

Property Specifiers

When specifying properties in a Jet filter or DASL filter using any of the above entry points, follow these guidelines:

	Jet Filter	DASL Filter
Applicable Properties	Most explicit built-in and custom item-level properties; see corresponding method topic for unsupported properties.	Most built-in and custom item-level properties with and without explicit string names; see corresponding method topic for unsupported properties.
Referencing Properties	By their explicit string names. Explicit built-in properties can only be referenced by their names in English and not any other localized language. Custom properties can be referenced by their names in English or a localized language.	By their namespaces.
Format of Reference	Enclose square brackets ('['']') around explicit string names. Property names are not case-sensitive. Spaces are not allowed in explicit built-in properties. Spaces are allowed in custom properties.	All DASL queries begin with a case-sensitive prefix "@SQL=", with the exception of DASL queries for Application.AdvancedSearch. Property referenced by namespace must be enclosed in double quotes. Property referenced by namespace are case-sensitive. If a space exists in the name of a custom property, the space must be replaced by "%20". In general, URL encoding applies the same way to characters in a DASL query as in a URL.
Error Conditions	Returns an error if a custom property in the filter is not defined, or the filter is empty, has an invalid argument, or cannot be parsed.	Returns an error if a custom property in the filter is not defined, or the filter is empty, has an invalid argument, or cannot be parsed.

Filter Syntax

The syntax of a filter depends on the type of the property you are filtering on. The following topics provide further information on how to construct a filter based on a specific property type:

• Filtering a Custom Field

• Filtering Items Using a Boolean Comparison

• Filtering Items Using a Comparison with a Keywords Property

• Filtering Items Using a Date-time Comparison

• Filtering Items Using a String Comparison

• Filtering Items Using a Variable

• Filtering Items Using an Integer Comparison

• Filtering Items Using Comparison and Logical Operators

• Filtering Items Using Query Keywords