Excellent! Let's review what we've learned in this part:

• You can define a window frame within OVER(...). The syntax is:

  [ROWS|RANGE] <WindowFrameDefinition>

• ROWS always treats rows individually (like the ROW_NUMBER() function)
• RANGE always adds rows that share the same value in the column we order by (like the RANK() function).
• The <WindowFrameDefinition> is defined by BETWEEN <LowerBound> AND <UpperBound>, where the bounds are defined using:
  • UNBOUNDED PRECEDING,
  • n PRECEDING (ROWS only),
  • CURRENT ROW,
  • n FOLLOWING (ROWS only),
  • UNBOUNDED FOLLOWING
• Remember that if <UpperBound> is equal to CURRENT ROW, you can use abbreviations and omit the <UpperBound>
  • [ROWS|RANGE] UNBOUNDED PRECEDING
  • [ROWS] n PRECEDING
  • [ROWS|RANGE] CURRENT ROW

So, are you ready for a short quiz?