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SQL Window Functions for Trends
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SQL Window Functions for Trends

MediumSQL · PostgreSQL

Problem

How would you implement a SQL window function to analyze trends over time?

Use the provided metric catalog and observations to calculate daily metric values and their cumulative values over time.

Output

  1. One row per metric and observation date with data.
  2. Return metric_name, metric_date, daily_value, and cumulative_value.
  3. Sort by metric_name, then metric_date ascending.

Schema

metric_catalog
ColumnTypeDescription
metric_idPKINTUnique metric identifier
metric_nameVARCHAR(100)Readable metric name
metric_observations
ColumnTypeDescription
observation_idPKINTUnique observation identifier
metric_idINTReferenced metric identifier
metric_dateDATEDate of the observation
metric_valueDECIMAL(12,2)Observed metric value
Tablesmetric_catalogmetric_observations
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