如何在 T-SQL 中使用最大值 Select 列？

Question

我正在嘗試找到銷售額最多的月份，我已經能夠使用以下方式顯示每個月的銷售額：

SELECT Month(orderdate)  AS Month, 
       Year(orderdate)   AS Year, 
       Sum(salesorderid) AS Sales 
FROM   sales.salesorderheader 
GROUP  BY Month(orderdate), 
          Year(orderdate) 

這表明

但我只想 select 銷量最高的月份。

Answer 1

如果我是正確的，您想打印具有最大銷售額的單個結果這里“salesorderid”是該月的總銷售額

• 嘗試添加 MAX

SELECT Month(orderdate)  AS Month, 
       Year(orderdate)   AS Year, 
       MAX(Sum(salesorderid)) AS Sales 
FROM   sales.salesorderheader 
GROUP  BY Month(orderdate), 
          Year(orderdate) 

• 或者嘗試使用 HAVING 子句

SELECT Month(orderdate)  AS Month, 
       Year(orderdate)   AS Year, 
       Sum(salesorderid) AS Sales 
FROM   sales.salesorderheader 
GROUP  BY Month(orderdate), 
          Year(orderdate) 
HAVING MAX(Sum(salesorderid))

因為 Sum(salesorderid) 是總銷售額，這可能有效......

Answer 2

您必須先按year group ，然后按month分組。 然后使用count()而不是sum() （似乎你的列是 SalesOrderID），但如果你試圖獲得sum of sales它應該類似於sum(salesamount) 。 還要更改您的column aliases ，這些是sql keywords 。

select month(OrderDate) as oMonth, year(OrderDate) as oYear
    , count(1) as SalesCount
from SalesOrderHeader
group by year(OrderDate), month(OrderDate)

獲得most number of sales 。

select top 1 * from (
    select month(OrderDate) as oMonth, year(OrderDate) as oYear
        , count(1) as SalesCount
    from SalesOrderHeader
    group by year(OrderDate), month(OrderDate)) t1
order by t1.SalesCount desc

Answer 3

只需使用top (1) ：

SELECT TOP (1) Month(orderdate)  AS Month, 
       Year(orderdate)   AS Year, 
       Sum(salesorderid) AS Sales 
FROM sales.salesorderheader 
GROUP BY Month(orderdate), Year(orderdate) 
ORDER BY Sales DESC;

Answer 4

你可以試試

1. 使用ORDER BY "字段名" DESC
2. 如果字段“ salesorderid ”不在類型編號中，則ORDER BY function 無法運行。 所以你可以改變之前，使用CAST("field name" AS Decimal)

檢查下面的代碼片段

SELECT Month(a.orderdate)  AS Month, 
       Year(a.orderdate)   AS Year, 
       Sum(a.salesorderid) AS Sales                                               
FROM   sales.salesorderheader  a
GROUP BY Month(a.orderdate),Year(a.orderdate) 
ORDER BY CAST(a.Sum(a.salesorderid), AS Decimal) DESC