Re: AND or UNION

Wong Chung Yin (cscywong_at_ug.cs.ust.hk) wrote:
: Hi,
: Which one is more efficient?
 

: 1. select * from empdemo where empdemo = 0 and empdemo = 1;

sorry . change to:

1. select * from empdemo where empdemo = 0 or empdemo = 1;

: 2. select * from empdemo where empdemo = 0
: union
: select * from empdemo where empdemo = 1;
Received on Thu Feb 13 1997 - 00:00:00 CST