For possible educational research purposes, I was playing around with a query that would randomly select people from a database. The database I experiment with has a group of fictitious persons with id numbers (primary key) ranging sequentially from 2 to 378. When I ran these queries below, I was expecting to select five random persons from the database. The query partially worked. I was getting random subjects, but everytime I ran the query, I got a different number of subjects, stretching from 0 and up (sometimes as many as 8 or 9). I could see the query generating fewer rows if I duplicated an id or made an off-by-one error, but I don't see how it could generate more than five. Does anyone see my error? (I've used two equivalent forms for the query below; both did the same thing)
select id,first,middle,last from persons where id = ceil(rand()*377+1) or id = ceil(rand()*377+1) or id = ceil(rand()*377+1) or id = ceil(rand()*377+1) or id = ceil(rand()*377+1); select id,first,middle,last from persons where id in (ceil(rand()*377 +1), ceil(rand()*377+1), ceil(rand()*377+1), ceil(rand()*377+1), ceil(rand()*377+1)); +------+-------------+--------+----------+ | id | first | middle | last | +------+-------------+--------+----------+ | 35 | Viridiana | W | McCarthy | | 47 | Crystal | O | Cassady | | 67 | Ricardo | L | Johnson | | 183 | Christopher | E | Denver | | 237 | Christopher | B | Brenner | | 255 | Danielle | W | Nickels | | 299 | Christine | D | Dexter | | 300 | Rachel | J | Baker | | 339 | Jenna | O | Murray | +------+-------------+--------+----------+ 9 rows in set (0.00 sec) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
