[SQL] Categories and subcategories : more details

[Rachel Coin]

> I have two tables : the first for categories and the second for
> subcategories.I want to get a result like Yahoo! For each category ,
> the sql
> query must return maximum 3 subcategories. I can't use "limit" in a
> subquery
> because I use Postgresql 7.0.

Examples : 

table CATEG :
ida     categ
 1        X
 2        Y
 3        Z 

table SUBCATEG :
idb     subcateg      ida
1           x1             1
2           x2             1
3           x3             1
4           x4             1
5           y1             2
6           y2             2
7           z1             3

I 'd like to obtain a table with maximum 2 subcateg per categ :

table result :

categ     subcateg
  X           x1
  X           x2
  Y           y1
  Y           y2
  Z           z1


any help?

Regards,


Rachel
 


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