Simon Willison’s Weblog

athena-sqlite (via) Amazon Athena is the AWS tool for querying data stored in S3—as CSV, JSON or Apache Parquet files—using SQL. It’s an interesting way of buliding a very cheap data warehouse on top of S3 without having to run any additional services. Athena recently added a query federation SDK which lets you define additional custom data sources using Lambda functions. Damon Cortesi used this to write a custom connector for SQLite, which lets you run queries against data stored in SQLite files that you have uploaded to S3. You can then run joins between that data and other Athena sources. # 18th December 2019, 9:05 am

datasette-template-sql (via) New Datasette plugin, celebrating the new ability in Datasette 0.32 to have asynchronous custom template functions in Jinja (which was previously blocked by the need to support Python 3.5). The plugin adds a sql() function which can be used to execute SQL queries that are embedded directly in custom templates. # 15th November 2019, 12:59 am

Calling C functions from BigQuery with web assembly (via) Google BigQuery lets you define custom SQL functions in JavaScript, and it turns out they expose the WebAssembly.instantiate family of APIs. Which means you can write your UDD in C or Rust, compile it to WebAssembly and run it as part of your query! # 27th October 2019, 5:55 am

SQL Murder Mystery in Datasette (via) “A crime has taken place and the detective needs your help. The detective gave you the  crime scene report, but you somehow lost it. You vaguely remember that the crime  was a murder that occurred sometime on ​Jan.15, 2018 and that it took place in SQL  City. Start by retrieving the corresponding crime scene report from the police  department’s database.”—Really fun game to help exercise your skills with SQL by the NU Knight Lab. I loaded their SQLite database into Datasette so you can play in your browser. # 7th October 2019, 11:37 pm

SQL queries don’t start with SELECT. This is really useful. Understanding that SELECT (and associated window functions) happen after the WHERE, GROUP BY and HAVING helps explain why you can’t filter a query based on the results of a window function for example. # 3rd October 2019, 8:56 pm

PugSQL. Interesting new twist on a definitely-not-an-ORM library for Python. With PugSQL you define SQL queries in files, give them names and then load them into a module which allows you to execute them as Python methods with keyword arguments. You can mark statements as only returning a single row (or a single scalar value) with a comment at the top of their file. # 3rd July 2019, 6:19 pm

Datasette: ?_where=sql-fragment parameter for table views. I just shipped a tiny but really useful new feature to Datasette master: you can now add ?_where=sql-fragment on to the URL of any table view to inject additional SQL directly into the underlying WHERE clause. This tiny feature actually has some really interesting applications: I created this because I wanted to be able to run more complex custom SQL queries without losing access to the conveniences of Datasette’s table view, in particular the built-in faceting support. The feature actually fits in well with Datasette’s philosophy of allowing arbitrary SQL to be executed against a read-only database: you can turn this ability off using the allow_sql config flag. # 13th April 2019, 2 am