sqlite joins with a single command across multiple db files

Whenever possible I like to have single commands in my bash history that perform one complete task. I rely heavily on fuzzy searching my history and if a given task is spread out over a few different commands, or if the task requires entering into some kind REPL, I’m much less likely to get value from my bash history.

Recently I spent some time figuring out how to perform a join query with sqlite when my tables are stored in separate db files without entering into the sqlite REPL. Here’s how to do it:

sqlite3 "" -cmd 'attach "system-a-hosts.db" as systema' -cmd 'attach "system-b-hosts.db" as systemb' "select * from systema.tablea as tablea left join systemb.tableb as tableb on tablea.name = tableb.host;"