将3个SQL查询合并为1个

我有3个查询需要合并成一个。给你

SELECT COUNT(e.EmployeeID) AS TotalEmpCount
FROM Employees as e
WHERE HomePhone <> ''

SELECT COUNT(e.EmployeeID) AS USEmpCount
FROM Employees as e
INNER JOIN Orders as o ON e.EmployeeID=o.EmployeeID
WHERE e.HomePhone <> '' AND e.Country='US' AND o.OrderDate BETWEEN '11/01/2011' AND GETDATE()


SELECT COUNT(e.EmployeeID) AS UKEmpCount
FROM Employees as e
INNER JOIN Orders as o ON e.EmployeeID=o.EmployeeID
WHERE HomePhone <> '' AND Country ='UK' AND o.OrderDate BETWEEN '01/01/2011' AND '12/31/2012'

我需要一个返回3列的查询：TotalEmpCount、USEmpCount、UKEmpCount

我需要T-SQL和Linq格式的查询

我自己解决了这个问题：

SELECT  (
        SELECT COUNT(*) 
FROM Employees as e
WHERE HomePhone <> ''
        ) AS TotalEmpCount,
        (
        SELECT COUNT(*)
FROM Employees as e
INNER JOIN Orders as o ON e.EmployeeID=o.EmployeeID
WHERE e.HomePhone <> '' AND e.Country='US' AND o.OrderDate BETWEEN '11/01/2011' AND GETDATE()
        )  AS USEmpCount,
        (
        SELECT COUNT(*)
FROM Employees as e
INNER JOIN Orders as o ON e.EmployeeID=o.EmployeeID
WHERE HomePhone <> '' AND Country ='UK' AND o.OrderDate BETWEEN '01/01/2011' AND '12/31/2012'
        )  AS UKEmpCount

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这将给您相同的结果：

SELECT COUNT(e.EmployeeID) AS TotalEmpCount,
    USEmpCount = SUM(CASE WHEN e.Country='US' AND o.OrderDate BETWEEN '11/01/2011' AND GETDATE() THEN 1 ELSE 0 END),
    UKEmpCount = SUM(CASE WHEN e.Country ='UK' AND o.OrderDate BETWEEN '01/01/2011' AND '12/31/2012' THEN 1 ELSE 0 END)
FROM Employees as e
LEFT JOIN Orders o
    ON e.EmployeeID = o.EmployeeID
WHERE HomePhone <> ''

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你可以通过问一个问题来改进你的问题。。。并展示你的1查询完成了什么以及你遇到了什么样的错误。如果我已经有一个查询，我可能一开始就不会问任何问题。展示你的尝试并询问你如何改进或使其发挥作用，比告诉我们你需要什么和期待答案要好得多。