Question

我有一个数据库，当我们将每个计算机制造和模型的名称存入我们的系统作为票证时，我存储名称。我想要汇总唯一值并显示一个表格，显示计算机制造商名称的显示位置。

即。

HP       30%
Dell     10%
Toshiba  40%
Sony     20%

我的查询看起来像是显示每个故障单中的每个事件。我不确定如何转换到上面的表格：

SELECT
  ComputerMake.ComputerMakeName
FROM
  Ticket
  INNER JOIN Asset ON Ticket.AssetID = Asset.AssetID
  INNER JOIN ComputerMake ON Asset.ComputerMakeID = ComputerMake.ComputerMakeID

我确信它总结了每个ComputerMakeName，但这超出了我的基本SQL经验！

先谢谢你。

Answer 1

首先，您需要计算每台计算机预订的次数，然后计算百分比：

SELECT
  ComputerMake.ComputerMakeName
 , count(*) * 100 / (select count(*) from FROM 
                      Ticket
                      INNER JOIN Asset ON Ticket.AssetID = Asset.AssetID
                      INNER JOIN ComputerMake ON Asset.ComputerMakeID = ComputerMake.ComputerMakeID) as count_computers
FROM 
  Ticket
  INNER JOIN Asset ON Ticket.AssetID = Asset.AssetID
  INNER JOIN ComputerMake ON Asset.ComputerMakeID = ComputerMake.ComputerMakeID
 group by ComputerMake.ComputerMakeName

Answer 2

考虑使用CTE来简化查询并避免冗余

WITH computer_CTE(computerName) AS
(
    SELECT ComputerMake.ComputerMakeName
    FROM Ticket
    INNER JOIN Asset ON Ticket.AssetID = Asset.AssetID
    INNER JOIN ComputerMake ON Asset.ComputerMakeID = ComputerMake.ComputerMakeID
)
Select computerName, (Count(*) * 100 / (Select Count(*) From computer_CTE)) as Percent
From computer_CTE
Group By computerName

SQL Sum命名并获取它们在数据库中出现的次数百分比

2 个答案: