Dne 18.2.2011 10:33, kokok_kokok napsal(a):

> How can I rewrite a non-correlated subquery to improve the performance?
>
> For example:
>
> SELECT
> (SELECT COUNT(*) FROM Orders) AS TotalOrders,
> Name
> FROM Customers

SELECT c.id, c.name, COUNT(DISTINCT o.id)
FROM customers c
LEFT JOIN orders o ON o.customer=c.id
GROUP BY 1, 2

Pepak