MS SQL - Count by range of data - sql

Question

I have a database of aircraft flight track data that cross certain points. I'm looking at the altitude that the aircraft crossed these points at and trying to bin them by every 100 ft. The altitudes range from about 2000 ft to 15000 ft so I want a way to do this that automates the 100 ft increments. So I want to have the crossing point, a range (say 2000-2100 ft), and the count. And the next line is the crossing point, the next range (2100-2200 ft), and the count, and so on.
I'm still a SQL newbie so any help to get me pointed in the right direction would be appreciated. Thanks.
Edited for clarity - I have nothing. I want a column with my crossing location, another with the altitude range, and a third with the count. I'm just not sure to bin the data so it will give me the ranges in 100 ft. increments.

Answer 1

You can use a calculated column for the AltitudeBucket. This is automatically calculated. (This technique is often used for loading dimension tables into data warehouses.)
In this case, having the AltitudeBucket as a calculated column means you can do calculations on it and use it in WHERE clauses.
Create and populate a table.
CREATE TABLE dbo.TrackPoint
(
TrackPointID int NOT NULL IDENTITY(1,1) PRIMARY KEY,
CrossingPoint nvarchar(50) NOT NULL,
AltitudeFeet int NOT NULL
CHECK (AltitudeFeet BETWEEN 1 AND 60000),
AltitudeBucket AS (AltitudeFeet / 100) * 100 PERSISTED NOT NULL
);
GO
INSERT INTO dbo.TrackPoint (CrossingPoint, AltitudeFeet)
VALUES
(N'Paris', 12772),
(N'Paris', 12765),
(N'Paris', 32123),
(N'Toulouse', 5123),
(N'Toulouse', 6123),
(N'Toulouse', 6120),
(N'Lyon', 15000),
(N'Lyon', 15010);
Display what's in the table.
SELECT *
FROM dbo.TrackPoint;
Run a SELECT query to calculate summarised counts.
SELECT CrossingPoint, AltitudeBucket, COUNT(*) AS 'Count'
FROM dbo.TrackPoint
GROUP BY CrossingPoint, AltitudeBucket
ORDER BY CrossingPoint, AltitudeBucket;
If you want to display the altitude range.
SELECT CrossingPoint, AltitudeBucket, CAST(AltitudeBucket AS nvarchar) + N'-' + CAST(AltitudeBucket + 99 AS nvarchar) AS 'AltitudeBucketRange', COUNT(*) AS 'Count'
FROM dbo.TrackPoint
GROUP BY CrossingPoint, AltitudeBucket
ORDER BY CrossingPoint, AltitudeBucket;

Answer 2

Whenever you're attempting to automate any kind of process, you first must design the algorithm for the process to successfully execute manually. To begin, pick out the smallest piece of this process: returning a count of altitudes between range x and x+100. So when x = 2000, you want to return all records between 2000 and 2100.
SELECT COUNT(*) FROM AltitudesTable
WHERE altitude >= 2000 AND altitude < 2100;
The above code works for one case: 2000 <= x < 2100.
To "automate," or loop through all cases, try using T-SQL:
DECLARE #x INT = 2000;
WHILE EXISTS(SELECT * FROM AltitudesTable)
BEGIN
SELECT COUNT(*) FROM AltitudesTable
WHERE altitude >= #x AND altitude < #x+100;
#x = #x+100;
END
Respectfully, your requirements are not solidly defined, so I had to make some assumptions regarding table structure and datatypes.