SQL-根据其他表格插入表格

Question

I am using SQL Server 2008. I have two tables, Stock and Usage. The fields of the tables are like below

Stock table

|itemid |batch  |qty     |date        |
---------------------------------------
|item1  |batch1 |20000   |2017-05-01  |
|item2  |batch1 |500     |2017-05-01  |
|item2  |batch2 |1000    |2017-05-02  |
|item2  |batch3_|1000    |2017-05-03  |

Usage table

|id    |itemid   |qty  |
------------------------       
|doc1  |item1    |8000 |
|doc1  |item2    |2000 |
|doc2  |item1    |500  |

I need to insert into other table where it will record what stock that have been used based on Usage table. I need to select the old stock first to be picked for the batch.

The desired table

|id     |itemid         |batch      |qty  |
-------------------------------------------
|doc1   |item1          |batch1     |8000 |
|doc1   |item2          |batch1     |500  |
|doc1   |item2          |batch2     |1000 |
|doc1   |item2          |batch3     |500  |
|doc2   |item1          |batch1     |500  |

I have come out with something like this. But how do I join the two tables. Or is there any other way to do this?

create usage_tmp
(
  no int identity,
  id nvarchar(20),
  itemid nvarchar(20),
  qty int
)

select no into #ControlTable
from usage_tmp


DECLARE @QTY INT,  
        @TABLEID INT,
        @QTYBAL INT
SET @QTYBAL = 0

WHILE EXISTS (SELECT * FROM #ControlTable)
BEGIN

    select top 1 @TableID = no
    from #ControlTable
    order by no  asc

    SET @QTY =  (SELECT top 1 QTY FROM usage_tmp)

    WHILE (@QTYBAL<@QTY)
    BEGIN
          INSERT INTO tbl_tmp
          SELECT * from stock


    END
    delete #ControlTable
    where no = @ID

end

drop table #ControlTable

Answer 1

仅两个表中没有足够的信息来系统地连接它们并解决此问题。