coming from a SQL Server background switching over to mysql hasn't been
that much fuss but i'm getting problems with computed fields.
in my head this should work,
select team_name, COUNT(team_id) as member_count
from members
where member_count = 2
group by team_name
now here this should basically group the members together and calculate
the members within each team, then only show the teams who have 2
members.
however when i run this it tells me,
undefined field 'member_count'
...can i not do a where clause on a computed field?, if so how can i get
around this?
appreciate any pointers you can give me?
MySQL doesn't support use of group aggregates in where clauses.
You instead have to use a "having" clause after the group clause.
ActiveRecord doesn't currently support a :having option to find.
I've been using a monkey patch that enables it, but you can always
use find_by_sql.