{"html_url": "https://github.com/simonw/datasette/issues/283#issuecomment-781670827", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/283", "id": 781670827, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MTY3MDgyNw==", "user": {"value": 9599, "label": "simonw"}, "created_at": "2021-02-18T22:16:46Z", "updated_at": "2021-02-18T22:16:46Z", "author_association": "OWNER", "body": "Demo is now live here: https://latest.datasette.io/_memory\r\n\r\nThe documentation is at https://docs.datasette.io/en/latest/sql_queries.html#cross-database-queries - it links to this example query: https://latest.datasette.io/_memory?sql=select%0D%0A++%27fixtures%27+as+database%2C+*%0D%0Afrom%0D%0A++%5Bfixtures%5D.sqlite_master%0D%0Aunion%0D%0Aselect%0D%0A++%27extra_database%27+as+database%2C+*%0D%0Afrom%0D%0A++%5Bextra_database%5D.sqlite_master", "reactions": "{\"total_count\": 0, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 0, \"eyes\": 0}", "issue": {"value": 325958506, "label": "Support cross-database joins"}, "performed_via_github_app": null}
{"html_url": "https://github.com/simonw/datasette/issues/283#issuecomment-781665560", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/283", "id": 781665560, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MTY2NTU2MA==", "user": {"value": 9599, "label": "simonw"}, "created_at": "2021-02-18T22:06:14Z", "updated_at": "2021-02-18T22:06:14Z", "author_association": "OWNER", "body": "The implementation in #1232 is ready to land. It's the simplest-thing-that-could-possibly-work: you can run `datasette one.db two.db three.db --crossdb` and then use the `/_memory` page to run joins across tables from multiple databases.\r\n\r\nIt only works on the first 10 databases that were passed to the command-line. This means that if you have a Datasette instance with hundreds of attached databases (see [Datasette Library](https://github.com/simonw/datasette/issues/417)) this won't be particularly useful for you.\r\n\r\nSo... a better, future version of this feature would be one that lets you join across databases on command - maybe by hitting `/_memory?attach=db1&attach=db2` to get a special connection.\r\n\r\nAlso worth noting: plugins that implement the [prepare_connection()](https://docs.datasette.io/en/stable/plugin_hooks.html#prepare-connection-conn-database-datasette) hook can attach additional databases - so if you need better, customized support for this one way to handle that would be with a custom plugin.", "reactions": "{\"total_count\": 0, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 0, \"eyes\": 0}", "issue": {"value": 325958506, "label": "Support cross-database joins"}, "performed_via_github_app": null}
{"html_url": "https://github.com/simonw/datasette/issues/283#issuecomment-781593169", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/283", "id": 781593169, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MTU5MzE2OQ==", "user": {"value": 9599, "label": "simonw"}, "created_at": "2021-02-18T19:47:34Z", "updated_at": "2021-02-18T19:47:34Z", "author_association": "OWNER", "body": "I have a working version now, moving development to a pull request.", "reactions": "{\"total_count\": 0, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 0, \"eyes\": 0}", "issue": {"value": 325958506, "label": "Support cross-database joins"}, "performed_via_github_app": null}
{"html_url": "https://github.com/simonw/datasette/issues/283#issuecomment-781591015", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/283", "id": 781591015, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MTU5MTAxNQ==", "user": {"value": 9599, "label": "simonw"}, "created_at": "2021-02-18T19:44:02Z", "updated_at": "2021-02-18T19:44:02Z", "author_association": "OWNER", "body": "For the moment I'm going to hard-code a `SQLITE_LIMIT_ATTACHED=10` constant and only attach the first 10 databases to the `_memory` connection.", "reactions": "{\"total_count\": 0, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 0, \"eyes\": 0}", "issue": {"value": 325958506, "label": "Support cross-database joins"}, "performed_via_github_app": null}
{"html_url": "https://github.com/simonw/datasette/issues/283#issuecomment-781574786", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/283", "id": 781574786, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MTU3NDc4Ng==", "user": {"value": 9599, "label": "simonw"}, "created_at": "2021-02-18T19:15:37Z", "updated_at": "2021-02-18T19:15:37Z", "author_association": "OWNER", "body": "`select * from pragma_database_list();` is useful - shows all attached databases for the current connection.", "reactions": "{\"total_count\": 0, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 0, \"eyes\": 0}", "issue": {"value": 325958506, "label": "Support cross-database joins"}, "performed_via_github_app": null}
{"html_url": "https://github.com/simonw/datasette/issues/283#issuecomment-781573676", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/283", "id": 781573676, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MTU3MzY3Ng==", "user": {"value": 9599, "label": "simonw"}, "created_at": "2021-02-18T19:13:30Z", "updated_at": "2021-02-18T19:13:30Z", "author_association": "OWNER", "body": "It turns out SQLite defaults to a maximum of 10 attached databases. This can be increased using a compile-time constant, but even with that it cannot be more than 62: https://stackoverflow.com/questions/9845448/attach-limit-10", "reactions": "{\"total_count\": 0, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 0, \"eyes\": 0}", "issue": {"value": 325958506, "label": "Support cross-database joins"}, "performed_via_github_app": null}
{"html_url": "https://github.com/simonw/datasette/issues/283#issuecomment-781077127", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/283", "id": 781077127, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MTA3NzEyNw==", "user": {"value": 9599, "label": "simonw"}, "created_at": "2021-02-18T05:56:30Z", "updated_at": "2021-02-18T05:57:34Z", "author_association": "OWNER", "body": "I'm going to to try prototyping the `--crossdb` option that causes `/_memory` to connect to all databases as a starting point and see how well that works.", "reactions": "{\"total_count\": 1, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 1, \"eyes\": 0}", "issue": {"value": 325958506, "label": "Support cross-database joins"}, "performed_via_github_app": null}
{"html_url": "https://github.com/simonw/datasette/issues/283#issuecomment-780991910", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/283", "id": 780991910, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MDk5MTkxMA==", "user": {"value": 9308268, "label": "rayvoelker"}, "created_at": "2021-02-18T02:13:56Z", "updated_at": "2021-02-18T02:13:56Z", "author_association": "NONE", "body": "I was going ask you about this issue when we talk during your office-hours schedule this Friday, but was there any support ever added for doing this cross-database joining?\r\n\r\nI have a use-case where could be pretty neat to do analysis using this tool on time-specific databases from snapshots\r\n\r\nhttps://ilsweb.cincinnatilibrary.org/collection-analysis/\r\n\r\n\r\n\r\nand thanks again for such an amazing tool!", "reactions": "{\"total_count\": 0, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 0, \"eyes\": 0}", "issue": {"value": 325958506, "label": "Support cross-database joins"}, "performed_via_github_app": null}