Re: Daily SQL Quiz

In article <1993May05.054053.2915@wvus.org> sford@wvus.org (Scott Ford) writes: >And now for today's SQL pop quiz: > >Suppose we have a table that contains a composite primary key on columns >task_id and instance_date. > >Now suppose that the table is populated with lots of data and we want to >get a listing of all tasks of a certain type, but only the latest date >for each type. Easy, right? > >Now suppose there's another column in the table that we want to select. >If it has differing values, we have a problem. This is because we'll get >a row back for every differnt value in that other column. > >If we are obstinate and refuse to use a programming language (other than >SQL) or a temporary table, can we still get the result we want? (I'm no expert, but) I believe that SQL allows recursive queries. Therefore, what you want would look like this (in pseudo-code): select * from Task where task_id = (select task_id from Task where max(instance_date)) -- --- Aahz Hugs and backrubs -- I break Rule 6 Kinky vanilla queer het I'm not a jerk, but I play one on the Net.