给定两条记录sql如何返回相交的年月数答案

【问题标题】：how to return number of intersecting years and months given two records sql给定两条记录sql如何返回相交的年月数
【发布时间】：2014-09-07 11:47:03
【问题描述】：

我有一个名为 Employee 的表。并且有三个列，分别命名为 start_date 和 end_date 和employee_name。

我正在编写存储过程，它接受两个员工（员工姓名）的 start_date 和 end_date，如果他们一起工作则返回 true，还返回他们一起工作的年数和月数。

所以我想要返回 john 和 kashif 一起工作的年数以及 bool 值 true 或 false（如果他们一起工作）的查询。

我该怎么做？

请任何人都可以帮助我，所以请这样做。

谢谢

【问题讨论】：

员工可以在该表上拥有多于 1 行（即多个开始日期和结束日期）还是总是只有一个日期范围？
Brian Demilia 员工在特定情况下只能有一行

标签： sql sql-server tsql sql-server-2012

【解决方案1】：

DECLARE @emp1 VARCHAR(10) = 'John'
DECLARE @emp2 VARCHAR(10) = 'Kashif'


SELECT CASE WHEN EXISTS (SELECT 1 FROM Emp
                         WHERE empID = @emp2
                          AND StartDate >= t.StartDate
                          AND EndDate   <= t.EndDate)
             THEN 1 ELSE 0 END  [Has Worked together]
      ,CASE WHEN EXISTS (SELECT 1 FROM Emp
                         WHERE empID = @emp2
                          AND StartDate >= t.StartDate
                          AND EndDate   <= t.EndDate)
             THEN DATEDIFF(DAY, CASE WHEN StartDate <= t.StartDate THEN StartDate ELSE t.StartDate END 
                             ,  CASE WHEN EndDate   >= t.EndDate   THEN EndDate   ELSE t.EndDate   END) 
                      ELSE 0 END  [Days worked together]
FROM Emp t
WHERE empID = @emp1

结果

Has Worked together      Days worked together
       1                            30

存储过程

CREATE PROCEDURE dbo.myProc 
@Employee1       VARCHAR(20),
@Employee2       VARCHAR(20),
@Worked_Together BIT OUTPUT,
@Days_Worked     INT OUTPUT
AS
BEGIN
  SET NOCOUNT ON; 

SELECT @Worked_Together 
        = CASE WHEN EXISTS (SELECT 1 FROM Emp
                            WHERE empID = @Employee2
                              AND StartDate >= t.StartDate
                              AND EndDate   <= t.EndDate)
                            THEN 1 ELSE 0 END  
      ,@Days_Worked  
         = CASE WHEN EXISTS (SELECT 1 FROM Emp
                              WHERE empID = @Employee2
                                AND StartDate >= t.StartDate
                                AND EndDate   <= t.EndDate)
             THEN DATEDIFF(DAY, CASE WHEN StartDate <= t.StartDate THEN StartDate ELSE t.StartDate END 
                             ,  CASE WHEN EndDate   >= t.EndDate   THEN EndDate   ELSE t.EndDate   END) 
                      ELSE 0 END  
FROM Emp t
WHERE empID = @Employee1        

END

【讨论】：

【解决方案2】：

检查这个查询：

DECLARE @Start_Date DATE ='2012/08/01'
DECLARE @End_Date DATE ='2014/08/01'

SELECT T1.ProfileName,
       T1.ProfileName,
       DATEDIFF(YEAR,CASE WHEN T1.START_DATE > T2.START_DATE THEN T1.START_DATE  ELSE T2.START_DATE                     End,CASE WHEN T1.End_DATE > T2.End_DATE THEN T2.End_DATE  ELSE T1.End_DATE End ) Years
FROM Tbl T1,Tbl T2 
WHERE T1.Start_Date  >= @Start_Date 
      AND T2.Start_Date >= @Start_Date
      AND T1.End_Date <= @End_Date 
      AND T2.End_Date <= @End_Date

【讨论】：