Basic aggregate functions

Time Series Analysis in SQL Server

Maham Faisal Khan

Senior Data Science Content Developer

Key aggregation functions

Counts

COUNT()

COUNT_BIG()

COUNT(DISTINCT)

Other Aggregates

SUM()

MIN()

MAX()

What counts with COUNT()

Number of Rows

COUNT(*)

COUNT(1)

COUNT(1/0)

Non-NULL Values

COUNT(d.YR)

COUNT(NULLIF(d.YR, 1990))

Distinct counts

SELECT
    COUNT(DISTINCT c.CalendarYear) AS Years,
    COUNT(DISTINCT NULLIF(c.CalendarYear, 2010)) AS Y2
FROM dbo.Calendar c;

Years	Y2
50	49

Filtering aggregates with CASE

SELECT
    MAX(CASE WHEN ir.IncidentTypeID = 1
            THEN ir.IncidentDate
            ELSE NULL
        END) AS I1,
    MAX(CASE WHEN ir.IncidentTypeID = 2
            THEN ir.IncidentDate
            ELSE NULL
        END) AS I2,
FROM dbo.IncidentRollup ir;

I1	I2
2020-06-30	2020-06-29

Let's practice!

Time Series Analysis in SQL Server