Question

我有两个包含开始和结束日期的SQL表。

 Table 1: Name, AddedDate
 Table 2: Name, RemovedDate

我正在寻找加入这两个表并将数据转储到临时表中，以显示何时添加名称和从列表中删除名称。

可能多次添加和删除相同的名称。

期望的输出示例

- Name, AddedDate, RemovedDate
- Jane, 2017-02-01, 2017-02-03
- Bill, 2017-01-28, (blank)
- Mike, 2017-01-15, 2017-01-19
- Jane, 2017-01-13, 2017-01-14

有人可以帮忙吗？谢谢。

Answer 1

另一个选项是 OUTER APPLY （如果是SQL Server）

示例

Declare @Table1 table (Name varchar(25),AddedDate date) Insert Into @Table1 Values ('Jane', '2017-02-01'), ('Bill', '2017-01-28'), ('Mike', '2017-01-15'), ('Jane', '2017-01-13') Declare @Table2 table (Name varchar(25),RemovedDate date) Insert Into @Table2 Values ('Jane', '2017-02-03'), ('Mike', '2017-01-19'), ('Jane', '2017-01-14') Select A.Name ,A.AddedDate ,B.RemovedDate From @Table1 A Outer Apply ( Select RemovedDate=min(RemovedDate) From @Table2 Where Name=A.Name and RemovedDate>=A.AddedDate ) B

<强>返回

Name AddedDate RemovedDate Jane 2017-02-01 2017-02-03 Bill 2017-01-28 NULL Mike 2017-01-15 2017-01-19 Jane 2017-01-13 2017-01-14

Answer 2

使用相关子查询仅考虑最后一次添加名称（并可能删除）......

select Name,
       AddedDate,
      (select max(RemovedDate)
         from table_2
        where Name=q1.Name
          and RemovedDate >= q1.AddedDate) as RemovedDate
 from (select Name,
              max(AddedDate) as AddedDate
         from table_1
        group by name) as q1
order by AddedDate desc,
         Name;

每次添加和删除名称时都会显示相同的相关子查询方法......

select Name,
       AddedDate,
      (select min(RemovedDate)
         from table_2
        where Name=q1.Name
          and RemovedDate >= t1.AddedDate) as RemovedDate
 from table_1 t1
order by AddedDate desc,
         Name;

Answer 3

您可以在名称上使用左连接

  select t1.name, t1.AddedDate, t2.RemovedDate
  from table1 t1 
  left join table2 t2 on t1.name = t2.name 
  order by name, t1.AddedDate, t2.RemovedDate

Answer 4

对于SQL Server使用以下脚本

;WITH CTE
AS
(
    SELECT
        SeqNo = ROW_NUMBER() OVER(PARTITION BY T1.Name ORDER BY T1.AddedDate DESC,T2.RemovedDate DESC)
        T1.Name,
        T1.AddedDate,
        T2.RemovedDate
        FROM Table1 T1 
            LEFT JOIN Table2 T2
                ON LTRIM(RTRIM(T1.name)) = LTRIM(RTRIM(T2.name))
)
SELECT
    *
    FROM CTE
    WHERE SeqNo = 1

如果您想要名称的所有记录，例如多次添加和删除名称并且您想要每个日期，那么只需执行

WHERE SeqNo = 1

部分

使用日期范围连接两个表

4 个答案: