I have two tables: products
and baskets
, which have the M2M
relation and the table name is basket_products
. I am trying to get the specific basket-related products
total price
and quantity, but I am getting stuck again. How can I fix the following code to get the result? note: I am using the Ent
framework
err = client.Basket.
Query().
Where(basket.ID(2)).
WithProducts().
QueryProducts().
GroupBy("price").
Aggregate(func(selector *sql.Selector) string {
return sql.As(sql.Sum("price"), "price")
}).Scan(ctx, &r)
if err != nil {
log.Println(err)
}
log.Println(r)
The Aggregate
and GroupBy
functions are the friends. Aggregation | Ent
I modified the code as given below and got a very optimized SQL
query, thanks to the Ent team.
err := client.Basket.
Query().
Where(basketEntity.ID(ID)).
GroupBy(basketEntity.FieldID).
Aggregate(func(s *sql.Selector) string {
t := sql.Table(product.Table)
joinT := sql.Table(basketEntity.ProductsTable)
s.Join(joinT).
On(s.C(basketEntity.FieldID), joinT.C(basketEntity.ProductsPrimaryKey[0]))
s.Join(t).
On(t.C(product.FieldID), joinT.C(basketEntity.ProductsPrimaryKey[1]))
return sql.As(sql.Sum(t.C(product.FieldPrice)), "price")
}).
Aggregate(repository.Count()).
Scan(ctx, &report)
The generated SQL
:
SELECT "baskets"."id", SUM("t2"."price") AS "price", COUNT(*)
FROM "baskets"
JOIN "basket_products" AS "t1" ON "baskets"."id" = "t1"."basket_id"
JOIN "products" AS "t2" ON "t2"."id" = "t1"."product_id"
WHERE "baskets"."id" = $1
GROUP BY "baskets"."id" args=[1]