https://github.com/janluksoft/tsqlpivot

An example of a complex T-SQL query
https://github.com/janluksoft/tsqlpivot

dynamic-sql ms-sql-server sql t-sql

Last synced: 5 days ago
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An example of a complex T-SQL query

• Host: GitHub
• URL: https://github.com/janluksoft/tsqlpivot
• Owner: janluksoft
• License: mit
• Created: 2022-12-09T09:21:27.000Z (almost 2 years ago)
• Default Branch: main
• Last Pushed: 2022-12-14T21:53:45.000Z (almost 2 years ago)
• Last Synced: 2024-09-24T18:57:45.336Z (9 days ago)
• Topics: dynamic-sql, ms-sql-server, sql, t-sql
• Language: TSQL
• Homepage:
• Size: 40 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# TSqlPivot

An example of a complex T-SQL query

## About project

The project shows an example of a complex T-SQL query whose elements are not available in SQL itself. 

These are variables, dynamic loops, queries, and subqueries. The original table [tb_speedcam_rec] 

contains a list of video recordings from several speed cameras. The speed camera number [cam_id] 

registration day [rec_start] and the size of the video file in bytes [fsize] are entered. 

The query creates a pivot table summing up the size of the recording files for the speed camera number 

[consecutive rows] and the day of the month [columns]. 

The query solves several difficulties one by one:

- Unequal date with hours is converted to date only;

- The volume of files is converted from int to floating decimal and expressed in the target number of gigabytes;

- Rows with 'null' are eliminated;

- A subquery is created which is then used by the second Select;

- The parameter int @jmon is created, where the period is narrowed down to a month;

- Grouping by cameras [jcam] and days [jdate_start] is created;

- Dynamic subqueries are created for the query: two lists with a unique list of days and cameras;

- From this, the Cartesian product of the columns [jSizeGb] and [jdate_start] is created (PIVOT pivot table);

- Lists eliminate many Null values and format data to string.

![](/Jpg/T-SQL_05.png)

## Running the script

To check the operation of the script, open the [SQLQuery_SpeedCameras.sql] file in Microsoft SQL Server Management Studio and run 'Execute'.