Zero, Unknown, and Not Applicable Deserve Different Answers

An empty attendance list can mean that nobody came or that nobody entered the attendance. A report that displays zero has chosen one of those explanations; it needs a reason. That distinction comes up in the reporting work for the Dayton Hash website. The pilot’s test cases distinguish confirmed empty attendance from unknown rosters and […]

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Decoding SQL’s Decode

I came across a SQL function I was not familiar with: decode. I looked it up and immediately replaced it with a CASE statement (in addition to other code cleanup). I’m afraid I don’t understand the existence of Oracle SQL’s decode() function: decode(expression, search, result [, search , result]… [, default] ) seems functionally equivalent […]

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Spikes, Slopes, and SQL

So you have data you’re tracking every day. Maybe a lot of data. Maybe tracking it a lot of ways. You might even have graphs of the data over time, so that you can spot trends and anomalies. And then you find that you’ve got too many graphs… It’s time to let the data tell […]

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