Question

I have two tables one with ID and NAME

table 1

ID | NAME
1  | first
2  | second
3  | third

and an XREF table with ID and PARENT ID

table2

ID | PARENT ID
1  | 0
2  | 1
3  | 2

and I would like to retrieve the NAME twice like this: NAME | PARENT NAME

If it is possible to go three levels deep but with same 2-column table like this:

result table

NAME   | PARENT NAME
first  | NULL or EMPTY or this line the not showing at all
second | first
third  | second

… then I’d like to figure that out as well.

Answer 1

select t1.Name, t12.Name from
table1 t1 
inner join table2 t2 on t1.ID = t2.ID 
inner join table1 t12 on t2.ParentID = t12.ID

This would only return 2 rows. If you want to have the first row (for ID=1) you just need to outer join instead.