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POBest way to show a user random data from an SQL database?
 

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  1. POBest way to show a user random data from an SQL database?
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    <p>I'm working on a web app in Python (Flask) that, essentially, shows the user information from a PostgreSQL database (via Flask-SQLAlchemy) in a random order, with each set of information being shown on one page. Hitting a Next button will direct the user to the next set of data by replacing all data on the page with new data, and so on.</p> <p>My conundrum comes with making the presentation truly random - not showing the user the same information twice by remembering what they've seen and not showing them those already seen sets of data again.</p> <p>The site has no user system, and the "already seen" sets of data should be forgotten when they close the tab/window or navigate away.</p> <p>I should also add that I'm a total newbie to SQL in general.</p> <p>What is the best way to do this?</p>
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    1. UScodegeek
    1. USJoshua Merriman
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    1. CO@MarkRichman - I don't think this is a duplicate, as I'm looking to get a random row that the user hasn't already seen, rather than just any random row. I'm also using SQLAlchemy, as opposed to actual SQL, to perform the queries
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      1. USJoshua Merriman
    2. CO_My conundrum comes with making the presentation truly random - not showing the user the same information twice by remembering what they've seen and not showing them those already seen sets of data again._ Just a nitpick: by definition, you are making your data LESS random by doing that. Perhaps that IS what you need your application to do, but you are throwing people off when you say you are trying to make things _truly_ random and then describe something that is _less_ random than just picking any element.
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      1. USMark Hildreth
    3. COAs @MarkHildreth said, what you are looking for isn't truly random. What I would ask then is if do you need as complicated a solution for your use case. First, how are you indexing data? If it is the usual auto-index starting with 1, you could just store your latest (aka highest index), and do a random number in that range. Example: `random_id = str(random.randint(1, latest_id))` then `SELECT * FROM data WHERE id = random_id`. Which would be a bit faster than 'order by RAND'. I believe you could query the latest id when flask started and store it in memory, and then update it when needed.
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      1. USSeberius
 

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