Where Element (Query)
Used within the context of a query to specify a filter.
The Where clause translates into the SQL SELECT statement. The format of the Where clause is a structured XML tree with a mixture of comparison operators, simple arithmetic operators, field (column) references, constant values, and predefined Collaborative Application Markup Language (CAML) constants.
Fields referenced in a Where element do not have to be fields of the primary list that is being queried. If a foreign list is being joined, then fields from the foreign list can be itemized in a ProjectedFields element and can then be referenced in the Where element.
In the following example, the Where element uses the Geq element as the filter in the query, returning cases where the date and time value in the Expires field is greater than today's date and time.