PrevVal

Find the last recorded value before a specified time.

Syntax

PrevVal(attname, t1)

Arguments

• attname

  The name of an attribute, enclosed in single quotation marks

• t1

  A time expression

Returns

The last recorded value before the specified time for the specified attribute

Exceptions

If there is no recorded value before the specified time, the function returns an error.

Example

• PrevVal('att1', '*')

  [Find and return the last recorded value of 'att1' before current time]

• PrevVal('att1', '15-Mar-17')

  [Find and return the last recorded value of 'att1' before start of day (12am) March 15th, 2017]