SQL
Special Values
There are also three special date values that can be used on input:  
<div class="narrow_table"></div>  
| Input string | Description                       |
|:-------------|:----------------------------------|
| epoch        | 1970-01-01 (Unix system day zero) |
| infinity     | later than all other dates        |
| -infinity    | earlier than all other dates      |  
The values `infinity` and `-infinity` are specially represented inside the system and will be displayed unchanged;
but `epoch` is simply a notational shorthand that will be converted to the date value when read.  
```sql
SELECT
'-infinity'::DATE AS negative,
'epoch'::DATE AS epoch,
'infinity'::DATE AS positive;
```  
| negative  |   epoch    | positive |
|-----------|------------|----------|
| -infinity | 1970-01-01 | infinity |