Configuration Manager 2007 supports a superset of the Windows Management Instrumentation (WMI) Query Language (WQL) known as Extended WQL. Both WQL and Extended WQL are retrieval-only languages that are used to create queries. Neither language can be used to create, modify, or delete classes or instances.

WQL and Extended WQL are based on the American National Standards Institute (ANSI) Structured Query Language (SQL) standard. However, they differ from standard SQL in that they retrieve from classes rather than tables and return instances rather than rows.

Extended WQL supports elements from two versions of ANSI SQL:

ANSI-92, which is the recommended version for most operations.

ANSI-89, which is primarily used only for JOIN operations by Open Database Connectivity (ODBC) applications requiring the services of the WMI ODBC Adapter.

Extended WQL includes a much broader range of operations than WQL. The following list shows the SELECT clauses that Extended WQL supports:

DISTINCT

COUNT

JOIN

WHERE

SUBSTRING

ORDER BY

UPPER, LOWER, and DATEPART functions

Because Extended WQL is fully case-insensitive, the UPPER and LOWER functions are not useful. Extended WQL supports the standard comparison operators (including LIKE and IN) and sub queries.

The SMS Provider does not support querying on system properties. System properties are those preceded by a double underscore prefix, for example __path.

Association queries are limited to the WQL syntax.

The use of COUNT and DISTINCT keywords together in a statement is not supported.

In Configuration Manager 2007 the WHERE clause supports GetDate(), DateDiff(), and DateAdd().

The ORDER BY clause does not work with the collection-limiting context qualifier.

See Also