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POConditional Query for Employee Training Analysis Query
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copied!<p>I need to run training queries that return results for questions like the following: "Who has completed this training, but not that training?"</p> <p>In the simplified table below, I would like to know which employee has completed training_id 1 (as indicated by a date in the completed_date field), but has not finished training_id 7.</p> <pre><code>+-------------+-------------+----------------+ | emp_id | training_id | completed_date | +-------------+-------------+----------------+ | 1 | 1 | 2010-04-02 | +-------------+-------------+----------------+ | 1 | 7 | Null | +-------------+-------------+----------------+ | 2 | 1 | Null | +-------------+-------------+----------------+ | 2 | 7 | Null | +-------------+-------------+----------------+ </code></pre> <p>Desired result would be emp_id 1 and we'd like to return his/her completed training and non-completed training per the query parameters:</p> <pre><code>+-------------+-------------+----------------+ | emp_id | training_id | completed_date | +-------------+-------------+----------------+ | 1 | 1 | 2010-04-02 | +-------------+-------------+----------------+ | 1 | 7 | Null | +-------------+-------------+----------------+ </code></pre> <p>I can't figure out how to do this with a regular query because it seems to need IF logic. Ex: Return rows where this one training is complete and return rows where this second training is not complete BUT ONLY if the first training is complete.</p> <p>How do I express something like that in SQL?</p>

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