I’m trying to do an update that requires table joins but I can’t find
any examples of updates beyond simple attribute value assignments. I
have a select statement like this:
SELECT title, state, name FROM posts, zips, states WHERE posts.zip_id =
zips.id AND states.abbreviation = zips.state;
The posts have a zip but not a state name yet. So I want to use an
update like this:
UPDATE posts, zips, states SET posts.state_id = state.id WHERE
posts.zip_id = zips.id AND states.abbreviation = zips.state;
I want to do this within a migration. I can’t find any examples of how
a migration like this should be handled. Does anyone know how to do
this, or where I can find more complex updates than simple attribute
value assignments?
Thanks,
David