SQL Server 2008：复杂插入

如何解决SQL Server 2008：复杂插入

| 我有一张叫ѭ0的表：

BeginYear  |   EndYear   |    Name
1974           1983           Robert

对于

Employees

中的每条记录，我需要将每年插入到名为

EmployeeYears

的新表中 所以：

For Each Record in Employees
    For i as int = Begin Year to End year
        INSERT i,Name into EmployeeYears

在SQL中执行此操作的任何方法...可能使用游标吗？     

解决方法

其要旨是使用WITH语句创建所有记录并将其插入到最终表中。

;WITH q AS (
  SELECT Year = BeginYear,Name
  FROM   Employees
  UNION ALL
  SELECT q.Year + 1,q.Name
  FROM   q
         INNER JOIN Employees e ON e.Name = q.Name
                                   AND e.EndYear > q.Year
)
INSERT INTO EmployeeYears
SELECT * FROM q
OPTION(MAXRECURSION 0)

测试数据

CREATE TABLE Employees (BeginYear INTEGER,EndYear INTEGER,Name VARCHAR(32))
CREATE TABLE EmployeeYears (Year INTEGER,Name VARCHAR(32))

INSERT INTO Employees
  SELECT 1974,1976,\'Robert\'
  UNION ALL SELECT 1972,1975,\'Lieven\'

结果

SELECT  *
FROM    EmployeeYears
ORDER BY Name,Year

1972    Lieven
1973    Lieven
1974    Lieven
1975    Lieven
1974    Robert
1975    Robert
1976    Robert

    ,如果您有数字表，则可以加入该表以获取各个年份的记录，并避免使用光标。我只是用从1965年到968年的数字填充了数字表，但是一个realife数字表（出于示例目的，它也不会是一个临时表，如下所示，但它存在于您的模式中）可能会有几百万条记录对于很多比较有用。

create table #Numbers (Number int)
insert into #Numbers
select 1965
union
select 1966
union 
select 1967
union 
select 1968

create table #employees (name varchar (50),beginyear int,endyear int)
insert into #employees
select \'Dick\',1966,1968
union all 
select \'harry\',1965,1967
union all 
select \'tom\',1955,1966

insert into EmployeeYears (Name,[Year])
select Name,n.number 
from #Employees e
join #Numbers n on  n.number between e.beginyear and e.endyear
order by name

    ,是的，您实际上必须做一个循环...我宁愿不使用CURSORS，但这种情况sorta还是有道理的...无论如何，这里的代码只是一个直接循环，向您展示了您可以做的事情SQL中的这种代码：

DECLARE @Employee VARCHAR(100)
DECLARE @BeginYear INT,@EndYear INT,@i INT

SET @Employee = \'\'

WHILE (1=1)
BEGIN
    SET @Employee = (SELECT TOP 1 Name FROM Employees ORDER BY Name WHERE Name > @Employee)

    IF @Employee IS NULL BREAK

    SELECT @BeginYear = BeginYear,@EndYear = EndYear FROM Employees WHERE Name = @Employee

    SET @i = @BeginYear

    WHILE (@i <= @EndYear)
    BEGIN
        INSERT INTO EmployeeYears (Year,Name) VALUES (@i,@Employee)
        SET @i = @i + 1
    END
END

    ,您可以使用递归CTE：

;WITH CTE AS
(
    SELECT BeginYear,EndYear,Name
    FROM Employees
    UNION ALL
    SELECT BeginYear+1,Name
    FROM CTE 
    WHERE BeginYear < EndYear
)  
INSERT INTO EmployeeYears (Year,Name)
SELECT BeginYear,Name
FROM CTE 
ORDER BY Name,BeginYear
OPTION(MAXRECURSION 0)

    ,您可以使用递归过程。就像一个波纹管：

CREATE Procedure InsertYear
    @Name ....
    @BeginYear ...
    @EndYear ...
AS
{
     INSERT INTO  EmployeeYears  VALUES(@BeginYear,@Name);
     SET  @BeginYear = @BeginYear + 1
     IF @BeginYear < @EndYear
     BEGIN
         InsertYear(@Name,@BeginYear,@EndYear)
     END

     RETURN
}

    ,您可以这样做，但是如果Begin或end超过2047，它将失败

INSERT INTO EmployeeYears (number,name)
SELECT v.number,e.name
FROM 
    Employees e
    INNER JOIN master..spt_values v on 
    v.number between beginYear and endYear