SQL
Evaluation
Here is a simple `ROW` frame query, using an aggregate function:  
```sql
SELECT points,
sum(points) OVER (
ROWS BETWEEN 1 PRECEDING
AND 1 FOLLOWING) we
FROM results;
```  
This query computes the `sum` of each point and the points on either side of it:  
<img src="/images/blog/windowing/moving-sum.jpg" alt="Moving SUM of three values" title="Figure 2: A moving SUM of three values" style="max-width:90%;width:90%;height:auto"/>  
Notice that at the edge of the partition, there are only two values added together.
This is because frames are cropped to the edge of the partition.