需要幫助以實現更漂亮的LINQ to SQL查詢

Question

以下是AdventureWorks數據庫的T_SQL查詢：

SELECT Name
FROM Production.Product
WHERE ListPrice >= ANY
(SELECT MAX (ListPrice)
FROM Production.Product
GROUP BY ProductSubcategoryID)

我嘗試為此編寫一個LINQ查詢：

        var groupMaxPricesquery2 = from product in dc.Products
                                   group product by product.ProductSubcategoryID into productGroup
                                   select productGroup.Max(eachProductInGroup => eachProductInGroup.ListPrice);

        var query = from product in dc.Products
                    where groupMaxPricesquery2.Any(listPrice => listPrice <= product.ListPrice)
                    select product.Name;

我怎樣才能使其更美觀（即將那些查詢組合在一起，或更有效的方法）？

非常感謝你

Answer 1

嘗試以下任一方法：

var query = from product in dc.Products
            let groupMaxPricesQuery = dc.Products.GroupBy(p => p.ProductSubcategoryID)
                                                 .Select(g => g.Max(item => item.ListPrice))
            where groupMaxPricesQuery.Any(listPrice => listPrice <= product.ListPrice)
            select product.Name;

// or
var query = dc.Products
              .Select(product => new {
                  Product = product,
                  GroupedMaxPrices = dc.Products.GroupBy(p => p.ProductSubcategoryID)
                                                .Select(g => g.Max(item => item.ListPrice))
            })
            .Where(item => item.GroupedMaxPrices.Any(listPrice => listPrice <= item.Product.ListPrice))
            .Select(item => item.Product.Name);

Answer 2

也許我在分組中缺少了一些東西，但是我不明白為什么有必要。

var maxListPrice = dc.Products.Max(p => p.ListPrice);
var query = dc.Products.Where(p => p.ListPrice >= maxListPrice).Select(n => n.Name);