Question

我只想获得一个值，即最大值，但在我添加p.Name之后，这个MAX不会工作。

SELECT 
    p.Name, MAX(r.TaxRate) AS TaxRate
FROM 
    Sales.SalesTaxRate r
JOIN 
    Person.StateProvince p ON r.StateProvinceID = p.StateProvinceID
JOIN 
    Person.CountryRegion c ON c.CountryRegionCode = p.CountryRegionCode
WHERE 
    c.Name = 'Canada'
GROUP BY 
    p.Name

Answer 1

使用RANK：

SELECT
    Name, TaxRate
FROM(
    SELECT 
        p.Name, 
        r.TaxRate,
        rn = RANK() OVER(ORDER BY r.TaxRate DESC)
    FROM Sales.SalesTaxRate r
    JOIN Person.StateProvince p
        ON r.StateProvinceID = p.StateProvinceID
    JOIN Person.CountryRegion c
        ON c.CountryRegionCode = p.CountryRegionCode
    WHERE
        c.Name = 'Canada'
)t
WHERE rn = 1

使用TOP WITH TIES

SELECT TOP 1 WITH TIES
    p.Name, 
    r.TaxRate
FROM Sales.SalesTaxRate r
JOIN Person.StateProvince p
    ON r.StateProvinceID = p.StateProvinceID
JOIN Person.CountryRegion c
    ON c.CountryRegionCode = p.CountryRegionCode
WHERE
    c.Name = 'Canada'
ORDER BY r.TaxRate DESC

SQL MAX只想获得一个值

1 个答案: