sql - 为每个映射生成新的行号

Question

我需要在映射表中为每个单元创建一个新的行号。请检查以下示例数据和预期结果。

Lines table
+--------+------------+------+------+
| FileId | linenumber | code | unit |
+--------+------------+------+------+
|      1 |          1 | A    | NULL |
|      1 |          2 | B    | NULL |
|      1 |          3 | C    | NULL |
+--------+------------+------+------+

map table
+------+------+
| code | unit |
+------+------+
| A    | c1   |
| A    | c2   |
| B    | c3   |
| B    | c4   |
| B    | c5   |
+------+------+

expected result
+--------+------------+------+------+
| FileId | Linenumber | code | unit |
+--------+------------+------+------+
|      1 |          1 | A    | c1   |
|      1 |          2 | B    | c3   |
|      1 |          4 | A    | c2   |
|      1 |          5 | B    | c4   |
|      1 |          6 | B    | c5   |
+--------+------------+------+------+

代码 A有两个单位( c1和 c2)，单位 c1将在行号 1中更新，并且 c2单位应作为新行插入行号在行表中最后一个可用行号之后。所有代码都应执行相同的过程

我目前的做法

if object_id('tempdb..#lines') is not null drop table #lines
if object_id('tempdb..#map') is not null drop table #map
if object_id('tempdb..#Files') is not null drop table #Files
if object_id('tempdb..#Maptemp') is not null drop table #Maptemp

create table #lines(FileId int, linenumber int, code varchar(10), unit varchar(10))
create table #map(code varchar(10), unit varchar(10))
insert into #lines values (1,1,'A',null), (1,2,'B',null),(1, 3,'C',null)
insert into #map values ('A','c1'),('A','c2'),('B','c3'),('B','c4'),('B','c5')

select FileId, MaxLinenum = max(linenumber) into #Files
    from #lines
    group by FileId

select row_number()over(partition by code order by (select null)) Rn,* into #Maptemp
    from #map

select l.FileId,l.Linenumber,l.code, m.unit
    from #lines l 
    inner join #Files f on l.FileId = f.FileId
    inner join #Maptemp m on m.code = l.code 
    where m.rn = 1
union all
select l.FileId, f.MaxLinenum +row_number()over(partition by f.FileId order by (select null)),l.code, m.unit
    from #lines l 
    inner join #Files f on l.FileId = f.FileId
    inner join #Maptemp m on m.code = l.code 
    where m.rn > 1

它工作正常，但是我觉得我为此做的编码很少。那么，有没有更好的方法来实现这一目标？

Answer 1

这是我的尝试。您可能需要根据实际架构进行一些更改。

DECLARE @MAXLINE INT = (SELECT MAX(linenumber) FROM #lines)

SELECT L.FileId
    ,CASE WHEN M.SNO = 1 THEN L.linenumber
        ELSE 
            @MAXLINE + ROW_NUMBER() OVER (PARTITION BY CASE WHEN M.SNO<>1
                THEN 1 END ORDER BY M.CODE ,M.UNIT)
        END LINE_NUMBER
, M.code
, M.unit
FROM #lines L
INNER JOIN
(
    SELECT ROW_NUMBER() OVER(PARTITION BY CODE ORDER BY(UNIT)) SNO,*
    FROM #map
)M ON L.code = M.code

结果:

FileId  LINE_NUMBER code    unit
1       1           A       c1
1       2           B       c3
1       4           A       c2
1       5           B       c4
1       6           B       c5