Walter Meester
HoogkarspelPays-Bas
Information générale
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
>Cetin
>
>You are refering to a recursive query, which I (I admit the mischaracterization as recursive CTEs can be use in creating records as well) referred to as for solving hierarchical problems. This is where I almost exclusively use them for.
>
>The challenge was to find me an example where using CTE as a subquery would lead to any significant advantage.
I've run into cases where I need the same subquery in multiple parts of a query. A CTE lets me write it once and use it repeatedly. Don't have an example handy, but it shouldn't be hard to think of one.
FWIW, I also find queries with CTEs (especially when there are several) far more readable than queries with lots of derived table. The case where I think readability is most aided is when otherwise, I'd have a long nested set of queries. In my view, those are so hard to read, and the CTE lays things out neatly so you can follow what's happening.
Tamar
Précédent
Suivant
Répondre
Voir le fil de ce thread
Voir le fil de ce thread à partir de ce message seulement
Voir tous les messages de ce thread
Voir tous les messages de ce thread à partir de ce message seulement