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Using a SQL Tokenizer

Imagine this: you have several directories full of SQL script files, and you need to know where a certain table is used. You’d rather like the context too, so you can check the whole SQL Expression and work out why it is running so slowly.

2024-01-08

SQLServerCentral Article

Dijkstra's Algorithm

Introduction This article celebrates a classic algorithm [1] of Dijkstra (1930 – 2002) which finds a path of minimal cost between any pair of nodes in an undirected graph. His procedure is widely recognized as a fundamental tool for examining communication and transportation networks (eg. Google Maps) and is surprisingly simple. By his own admission, […]

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2024-01-05

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Question of the Day

The LAGging NULL

I have this data in a SQL Server 2022 table:

player         yearid team HR
Alex Rodriguez 2012   NYY  18
Alex Rodriguez 2013   NYY  7
Alex Rodriguez 2014   NYY  NULL
Alex Rodriguez 2015   NYY  12
Alex Rodriguez 2016   NYY  9
If I run this code, what are the results returned in the hrgrowth column?
SELECT
  player
, yearid
, hr
, hr - LAG (hr, 1, 0) IGNORE NULLS OVER (ORDER BY yearid) AS hrgrowth
FROM dbo.playerstats;

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