It all started because I was curious about the maximum streak in professional SC2 esports. To my surprise, despite all the data available on so many sites, apparently no one had ever looked into it - so I downloaded a dump of Aligulac and created a first list on my own. However, this was a one-off and took a long time (the Excel file was over one GB in size and threatened to crash a few times), and it didn't allow other parameters (like certain races/countries). So I set up this website (the URL being a equivalent to my other website, D3Resource).
I mirror a daily snapshot from Aligulac as they provide a dump of their DB. Then I create a materialized view of all matches with all the info I want to have as additional columns. That allows me to have a cached overview of all the data, so I "only" need to filter for streaks. Since every match is in there twice (from either player's perspective) this view currently has ~570k rows. Here's the SQL if you're interested. The web interface then creates a query based on your parameters to get the streaks - here's the code for that (the indented line 15 is where all the parameters are being added). The other queries for the other sites are a bit simpler, but I can share if you're interested.
If you think this is all super bullshit and bad SQL practice or it looks terrible and you think it can be improved - you're probably right! I'm not an expert in SQL and just do all this stuff for fun and to occasionally refresh my ~20 year old web design/DB/programming skills. Please contact me on Reddit or via email if you want to help (either with design, DB stuff, or anything else)!