declare @T table (ID varchar(3),[User] varchar(2),Date varchar(2),Flow varchar(2))
insert into @T
select 'id1','u1','d1','f1' union all
select 'id1','u2','d2','f2' union all
select 'id1','u3','d3','f3' union all
select 'id2','u4','d4','f2' union all
select 'id2','u5','d5','f3'

select id,
    f1_user=max(case when flow='f1' then [user] else '' end),
    f1_date=max(case when flow='f1' then date else '' end),
    f2_user=max(case when flow='f2' then [user] else '' end),
    f2_date=max(case when flow='f2' then date else '' end),
    f3_user=max(case when flow='f3' then [user] else '' end),
    f3_date=max(case when flow='f3' then date else '' end)
from @t group by id
/*
id   f1_user f1_date f2_user f2_date f3_user f3_date
---- ------- ------- ------- ------- ------- -------
id1  u1      d1      u2      d2      u3      d3
id2                  u4      d4      u5      d5
*/

------解决方案--------------------
SQL code

create table tb(ID varchar(10),[User] varchar(10),Date varchar(10),Flow varchar(10))
insert into tb
select 'id1' ,'u1' ,'d1' ,'f1' union all
select 'id1' ,'u2' ,'d2' ,'f2' union all
select 'id1' ,'u3' ,'d3' ,'f3' union all
select 'id2' ,'u4' ,'d4' ,'f2' union all
select 'id2' ,'u5' ,'d5' ,'f3'
go

declare @sql varchar(8000)
set @sql = 'select ID'
select @sql = @sql + ',max(case Flow when '''+Flow+''' then [User] else '''' end) as ['+Flow+'_User]'
                   + ',max(case Flow when '''+Flow+''' then Date else '''' end) as ['+Flow+'_Date]'
from (select distinct Flow from tb)t
select @sql = @sql + ' from tb group by ID'
exec(@sql)

drop table tb

/**********

ID         f1_User    f1_Date    f2_User    f2_Date    f3_User    f3_Date
---------- ---------- ---------- ---------- ---------- ---------- ----------
id1        u1         d1         u2         d2         u3         d3
id2                              u4         d4         u5         d5

(2 行受影响)