Spiega una funzione SQL

Spiega uno snippet di codice SQL.

Puoi eseguire query direttamente su un modello e testare i risultati restituiti quando utilizzi valori parametro diversi con la console Cloud o chiamando direttamente l'API Vertex AI.

Richiesta in formato libero


Explain the function of `CROSS APPLY` in the code below:

```sql
SELECT customer.CustomerId, customer.CustomerName, ord.*
FROM customers customer
CROSS APPLY
(
    SELECT SUM(order.quantity) as TotalQuantity
    FROM orders order
    WHERE order.CustomerId = customer.CustomerId
) ord;
```

                

Risposta


The `CROSS APPLY` operator in the provided SQL code performs a lateral join,
which allows you to access data from a related table for each row in the outer
table. In this case, the outer table is the `customers` table, and the related
table is the `orders` table.

The `CROSS APPLY` operator is used to calculate the total quantity of orders for
each customer. The subquery within the `CROSS APPLY` operator calculates the sum
of the `quantity` column from the `orders` table for each customer. The result
of the subquery is then assigned to the alias `ord`, which is used to access the
calculated total quantity in the outer query.

The output of the query will be a table that contains the following columns:

*   `CustomerId`
*   `CustomerName`
*   `TotalQuantity`

For each row in the `customers` table, the query will calculate the total
quantity of orders placed by that customer.

              
Modello: gemini-1.0-pro-001
Temperatura: 0.2
Numero massimo di token di output: 2048
TopK: 40
TopP: 0,95