Q:

SQL lookup against list and insert

I have a list of IDs that I would like to reference against a database table and insert into an empty table. 
Temp order table 1
20
23
35
36

.....
Table 2 product table
product1, 20, x, y, z
product2, 20, x, y, z
product3, 23, x, y, z
product4, 20, x, y, z
product5, 23, x, y, z
product6, 27, x, y, z
product7, 29, x, y, z
product8, 27, x, y, z

Table 3 (expect output)
Product1, a, b, c
Product2, a, b, c
Product4, a, b, c
Product3, a, b, c
Product5, a, b, c

I would like your kind assistance of processing each item in table 1 against table 2 to populate an initially empty table 3 so that each matching record is inserted.  Probably a fairly common task, but I cant seem to get my head around it! 

A:

I believe what you are looking for is
insert into Table3
select t2.product,t2.letter1,t2.letter2,t2.letter3 
from Table 1 t1
inner join Table 2 t2 on t1.number = t2.number

Not sure if you need a where clause since I can't really see what you would be filtering on unless it would be the letter in which case just add 
where t2.letter1 =x and t2.letter2 = y, and t2.letter3 = z

