[Solved] You want to calculate a moving average of sales amounts over the last 7 days including the current day, but your sales table has... Which window frame clause correctly computes this using RANGE? | PostgreSQL

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You want to calculate a moving average of sales amounts over the last 7 days including the current day, but your sales table has multiple sales per day. Which window frame clause correctly computes this using RANGE?

ARANGE BETWEEN INTERVAL '7 days' PRECEDING AND CURRENT ROW

BRANGE BETWEEN INTERVAL '6 days' PRECEDING AND CURRENT ROW

CROWS BETWEEN 6 PRECEDING AND CURRENT ROW

DROWS BETWEEN 7 PRECEDING AND CURRENT ROW

Step-by-Step Solution

Solution:

Step 1: Understand the requirement
We want a 7-day moving average including current day, so the frame covers 6 days before plus current day (total 7 days).
Step 2: Choose correct frame type
Since multiple sales per day exist, using RANGE with INTERVAL ensures all rows within date range are included.
Step 3: Select correct interval
INTERVAL '6 days' PRECEDING to CURRENT ROW covers 7 days total (6 before + current).
Final Answer:
RANGE BETWEEN INTERVAL '6 days' PRECEDING AND CURRENT ROW -> Option B
Quick Check:
Use RANGE with 6 days preceding for 7-day window [OK]

Quick Trick: RANGE with INTERVAL covers value ranges, perfect for dates [OK]

Common Mistakes:

Using ROWS which counts rows, not days
Choosing wrong interval length
Confusing 6 days preceding with 7 days

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Which window frame clause correctly computes this using RANGE?

Step 1: Understand the requirement

Step 2: Choose correct frame type

Step 3: Select correct interval

Final Answer:

Quick Check:

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