help with interesting 'query'

hi

        i need the 'groups' help with a query. hopefully someone will be able to help. i have two tables ...

create table foo
(

	id	varchar (10)
	f1	varchar (5)
	f2	int
	f3	varchar (5)
	f4	int
	f5	varchar (5)
	f6	int
	f7	varchar (5)
	f8	int

	id	varchar (10)
	f1	varchar (5)
	f2	int
	f3	varchar (5)
	f4	int
	f5	varchar (5)
	f6	int
	f7	varchar (5)
	f8	int

one is obviously a copy of the other. the contents of foo will be overriden on a daily basis - we purchase our data from an outside provider. however, we extend the data by changing the value of some subset of the non-primary key fields (id is the primary key). i need to be able to perform a query that given an 'id' will retrieve any non null values from fooExtended but if a field is null in fooExtended will retrieve its value from foo.

        i realize that one way of solving this is to make fooExtended a complete copy of foo when and if we extend any of its values - but that is expensive in terms of storage. i'm hoping to use a more efficient/elegant solution.

        here's another question....

        is it possible to programmatically supply a table name, the fields and predicates used in a query ? for instance

exec doQuery 'employee', 'emp_id, fname, lname', 'where fname like a%'

doQuery is a stored procedure that programmatically 'builds' a query. the above will result in the following query being built

select emp_id, fname, lname
from employee
where fname like 'a%'

for what its worth i'm using ms-sql server 6.5.

any help would be greatly appreciated.

thanks
dave Received on Mon Aug 17 1998 - 00:00:00 CEST