Items tagged sql in 2023
Filters: Year: 2023 × sql × Sorted by date
Making PostgreSQL tick: New features in pg_cron (via) pg_cron adds cron-style scheduling directly to PostgreSQL. It's a pretty mature extension at this point, and recently gained the ability to schedule repeating tasks at intervals as low as every 1s.
The examples in this post are really informative. I like this example, which cleans up the ever-growing cron.job_run_details table by using pg_cron itself to run the cleanup:
SELECT cron.schedule('delete-job-run-details', '0 12 * * *', $$DELETE FROM cron.job_run_details WHERE end_time < now() - interval '3 days'$$);
pg_cron can be used to schedule functions written in PL/pgSQL, which is a great example of the kind of DSL that I used to avoid but I'm now much happier to work with because I know GPT-4 can write basic examples for me and help me understand exactly what unfamiliar code is doing. # 27th October 2023, 2:57 am
Upsert in SQL (via) Anton Zhiyanov is currently on a one-man quest to write detailed documentation for all of the fundamental SQL operations, comparing and contrasting how they work across multiple engines, generally with interactive examples.
Useful tips in here on why “insert... on conflict” is usually a better option than “insert or replace into” because the latter can perform a delete and then an insert, firing triggers that you may not have wanted to be fired. # 25th September 2023, 8:34 pm
Online gradient descent written in SQL (via) Max Halford trains an online gradient descent model against two years of AAPL stock data using just a single advanced SQL query. He built this against DuckDB—I tried to replicate his query in SQLite and it almost worked, but it gave me a “recursive reference in a subquery” error that I was unable to resolve. # 7th March 2023, 6:56 pm