# OBIEE - Last/First function (Point in Time measure)

Function that selects the first/last returned value of the expression argument.

Syntax:

``````FIRST (expression)
LAST (expression)```
```

where expression is any expression.

## Limitations

You cannot use it in Logical SQL statements. It must be used in the repository.

## Implementation

By default, the FIRST/LAST function operates at the most detailed level specified of all dimension.

For example, if you have:

• a time dimension defined with hierarchy levels year, month, day
• a geographic store dimension defined with hierarchy levels county, state, zip, store

the FIRST/LAST function returns the first/last value for the combination day/store on each level. (i.e. even if the report asks a month summary for instance).

To limit the FIRST/LAST function, you must define an dimension-specific aggregation rules in the repository.