sql - 如何从将多行返回到单个结果的查询中获得 "merge"、 "flatten"或 "pivot"结果？

Question

我有一个对表的简单查询，它返回如下结果:

id    id_type  id_ref
2702  5        31
2702  16       14
2702  17       3
2702  40       1
2703  23       4
2703  23       5
2703  34       6
2704  1        14

我想将结果合并到一行中，例如:

id    concatenation 
2702  5,16,17,40:31,14,3,1
2703  23,23,34:4,5,6
2704  1:14

有没有办法在触发器中做到这一点？

注意:我知道我可以使用游标，但除非没有更好的方法，否则我真的不想这样做。

数据库是 Sybase 版本 12.5.4。

Answer 1

由于使用 select 语句在 Sybase 中完成此操作相当困难，因此我建议使用 while循环如下。虽然循环比游标更受欢迎，因为它要快得多。假设表名是 MYTABLE:

CREATE TABLE #temp
(                               
aa            numeric(5,0)  identity,                            
id            int           not null,
id_type       int           not null,
id_ref        int           not null
)

CREATE TABLE #results
(                                                        
id            int           not null,
concatenation varchar(1000) not null,
)

insert into #temp
select id, id_type, id_ref from MYTABLE order by id

declare @aa int, @maxaa int, @idOld int, @idNew int
declare @str1 varchar(1000), @str2 varchar(1000)

set @aa = 1
set @maxaa = (select max(aa) from #temp) 
set @idNew = (select id from #temp where aa = 1) 
, @idOld = @idNew

while @aa <= @maxaa 
    begin
        set @idNew = (select id from #temp where aa = @aa) 
        IF @idNew = @idOld
          BEGIN
             set @str1 = @str1 + convert(varchar,(select id_type from #temp where aa = @aa)) + ','  
             , @str2 = @str2 + convert(varchar,(select id_ref from #temp where aa = @aa)) + ','

             IF @aa = @maxaa  
             insert into #results (id, concatenation) 
             VALUES (@idOld, left(@str1,len(@str1) - 1) + ':' + left(@str2,len(@str2) - 1) )

          END
        ELSE
          BEGIN
             insert into #results (id, concatenation) 
             VALUES (@idOld, left(@str1,len(@str1) - 1) + ':' + left(@str2,len(@str2) - 1) )
             set @str1 = NULL, @str2 = NULL
             set @str1 = @str1 + convert(varchar,(select id_type from #temp where aa = @aa)) + ','  
             , @str2 = @str2 + convert(varchar,(select id_ref from #temp where aa = @aa)) + ',' 

             IF @aa = @maxaa  
             insert into #results (id, concatenation) 
             VALUES (@idNew, left(@str1,len(@str1) - 1) + ':' + left(@str2,len(@str2) - 1) )
          END

        set @idOld = @idNew 
        set @aa = @aa+1
    end

select * from #results

编辑
以下版本快了约 45%

CREATE TABLE #temp
(                               
aa            numeric(5,0)  identity,                            
id            int           not null,
id_type       int           not null,
id_ref        int           not null
)

CREATE TABLE #results
(                                                        
id            int           not null,
concatenation varchar(1000) not null,
)

insert into #temp
select id, id_type, id_ref from MYTABLE order by id
declare @aa int, @maxaa int, @idOld int, @idNew int
declare @str1 varchar(1000), @str2 varchar(1000), @j int

set @aa = 1
set @maxaa = (select max(aa) from #temp) 
set @idNew = (select id from #temp where aa = 1) 
, @idOld = @idNew
set @str1 = ':'

while @aa <= @maxaa 
    begin
        set @idNew = (select id from #temp where aa = @aa) 
        IF @idNew = @idOld
          BEGIN
             set @str2 = (select convert(varchar,id_type) + ':' + convert(varchar,id_ref) from #temp where aa = @aa)
             set @j = (select charindex(':',@str2))
             set @str1 = str_replace(@str1, ':', substring(@str2,1,@j - 1) + ',:') + right(@str2,len(@str2) - @j) + ',' 

             IF @aa = @maxaa  
             insert into #results (id, concatenation) 
             VALUES (@idOld, left(str_replace(@str1, ',:', ':'),len(@str1) - 2) )

          END
        ELSE
          BEGIN
             insert into #results (id, concatenation) 
             VALUES (@idOld, left(str_replace(@str1, ',:', ':'),len(@str1) - 2) )
             set @str1 = ':'
             set @str2 = (select convert(varchar,id_type) + ':' + convert(varchar,id_ref) from #temp where aa = @aa)
             set @j = (select charindex(':',@str2))
             set @str1 = str_replace(@str1, ':', substring(@str2,1,@j - 1) + ',:') + right(@str2,len(@str2) - @j) + ','

             IF @aa = @maxaa  
             insert into #results (id, concatenation) 
             VALUES (@idNew, left(str_replace(@str1, ',:', ':'),len(@str1) - 2) )
          END

        set @idOld = @idNew 
        set @aa = @aa+1
    end

select * from #results