For examples suppose you have a customer database with a Customer table: cust_id cust_name 111 Liam Clarke 222 Kent Johnson
and a Customer_Order table (way oversimplified): cust_id order_date 111 2004-4-22 111 2004-5-6 222 2004-1-31 111 2005-2-1
To show all customer orders with the customer id and name, you would join these two tables on the cust_id column:
select c.cust_id, c.cust_name, co.order_date from Customer c, Customer_Order co where c.cust_id = co.cust_id
To get just Liam's orders, add another clause to the above: ... and c.cust_id = '111'
Anyway, why don't you tell us more about what you are trying to do and we can give better suggestions.
Kent
Liam Clarke wrote:
Hi,
Working my way through the basics of SQL, and I can see that it's very powerful for searching by different criteria.
I'm already hitting my conceptual troubles however, as I'm visualising each table as a 'card'. Always my problems, too much imagination. But yeah, it seems very 1 dimensional. But what I was wondering was is it possible within the bounds of SQL to contain a SQL query reference as a value, so that retrieving a certain value retrieves the results of that query i.e.
table foo
a b c
1 2 select d from bar
table bar
d e f
3 4 5
and select c from foo retrieves d from bar? I know I'm leapfrogging way ahead of myself, and probably confusing myself unnecessarily, but I'm just trying to make my cards more 3D in terms of linking data....
Any assistance for my vague question gratefully appreciated.
Regards,
Liam Clarke
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