NumOfChanges

Return the number of changes in value for an attribute within a specified time range.

Syntax

NumOfChanges(attname, starttime, endtime)

Arguments

• attname

  The name of an attribute

• starttime

  A time expression that specifies the start of a time range, or a time span (such as '-3h') that specifies the start time relative to endtime; entries must be enclosed in single quotation marks

• endtime

  A time expression that specifies the end of a time range, or a time span (such as '+3h') that specifies the end time relative to startime; entries must be enclosed in single quotation marks

Returns

The count of changes in value for attname in the specified time range excluding bad values

Example

• NumOfChanges('att1', 't', '*')

  [Return the number of times the value of 'att1' changed since midnight until now]