Question

我有一个查询，我试图计算每个员工的电话数量。但是，Employee的名称不在Call的表中，所以我不得不使用Inner Join。这是我到目前为止所拥有的。我正在使用SQL Server 2008 R2

Select e.Name, count(1)
From Employees e INNER JOIN Calls c on c.EmployeeID = e.TechID
Where(c.Name LIKE 'John ') OR 
     (c.Name LIKE 'Sam ') OR 
     (c.Name LIKE 'Bob ') OR 
     (c.Name LIKE 'Mark') OR 
     (c.Name LIKE 'Mike')  
Group By e.Name

基本上我正在寻找两个列，即员工的姓名和他们拨打的电话号码。

查询将会运行，但它会持续很长时间，直到我最终杀死它。有更好的方法吗？

Answer 1

试试这个..

Select e.Name, count(*) Total_Calls
From Employees e INNER JOIN Calls c on c.EmployeeID = e.TechID
Where c.Name IN ('John ','Sam ','Bob ','Mark ','Mike ')  
Group By e.Name

Answer 2

尝试在子查询中进行聚合，然后将其加入到employee表中。

SELECT 
    A.[Name],
    B.[CallCount]
FROM [Employees] A
INNER JOIN (SELECT [EmployeeID], COUNT(*) [CallCount] FROM [Calls] GROUP BY [EmployeeID]) B
ON      A.[TechID] = B.[EmployeeID]
WHERE   A.[Name] LIKE 'John '
     OR A.[Name] LIKE 'Sam '
     OR A.[Name] LIKE 'Bob '
     OR A.[Name] LIKE 'Mark'
     OR A.[Name] LIKE 'Mike'

Answer 3

我同意格里坦。你的字符串处理（分组和搜索）是罪魁祸首。您可以将临时表中的员工ID存储在搜索条件中，然后在主查询中按员工ID分组并查找临时表中匹配的ID

CREATE #temptable
(int id)


SELECT e.Id
INTO #temptable
FROM Employees e
WHERE (e.Name LIKE 'John ') OR 
     (e.Name LIKE 'Sam ') OR 
     (e.Name LIKE 'Bob ') OR 
     (e.Name LIKE 'Mark') OR 
     (e.Name LIKE 'Mike')  


Select e.Name, count(1)
From Employees e INNER JOIN Calls c on c.EmployeeID = e.TechID
Where e.Id IN (
   SELECT Id FROM #temptable
)
Group By e.Id

使用内部联接计数记录

3 个答案: