count of unique emails from several tables

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count of unique emails from several tables

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Last edited Oct 16, 2013

Created on Oct 16, 2013

This example counts unique email addresses across three monthly developer tables by combining them with UNION and applying SELECT DISTINCT COUNT(*). The SQL query nests three SELECT statements inside a UNION, each pulling the email column from a separate table (active_developers_april2013, february2013, and march2013), before counting the deduplicated results. It demonstrates a straightforward approach to aggregating overlapping datasets, with the gist’s code showing only the SQL logic and no visualization library or rendering API.

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