Use golf analogy when explaining to executives. Use a car analogy for all others. — Confucius. The purpose of window functions is to translate the business reporting requirements declaratively and effectively to SQL so query performance and developer/business-analyst efficiency improve dramatically. I’ve seen real-world reports and dashboards go from hours to minutes, minutes to seconds after using window functions. Query size decreases from 40-pages to a few pages. Back in the ‘90s, Redbrick database really understood the business use case and created a new layer of functionality to do business reporting that included ranking, running totals, calculating commissions & inventory based on subgroups, positions, etc. These have been in SQL standard in 2003. Every BI layer (like Tableau, Looker, Cognos) exploits this functionality. Introduction to...
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