使用拆分函数重构表SQL

Question

我目前正在尝试学习分割功能以及如何实际使用分割功能。我有一张桌子，我需要拆分并认为我需要使用拆分（因此试图学习）。但是我很困惑如何使它工作！

使用excel作为模拟第一组数据就是这样的。第二组是我希望它如何追求。

有人可以帮忙吗？

Answer 1

对每个列使用string split function，并使用union all后跟pivot合并结果，以正确的方式检索您的值。

select P.SaveName, P.Para1, P.Para2, P.Para3, P.Para4, P.Para5, P.Para6
from (
     select T.SaveName, S.ID, S.Item, S.Para
     from YourTable as T 
       cross apply (select ID, Item, 'Para1' from dbo.SplitString(T.Para1, ',') union all
                    select ID, Item, 'Para2' from dbo.SplitString(T.Para2, ',') union all
                    select ID, Item, 'Para3' from dbo.SplitString(T.Para3, ',') union all
                    select ID, Item, 'Para4' from dbo.SplitString(T.Para4, ',') union all
                    select ID, Item, 'Para5' from dbo.SplitString(T.Para5, ',') union all
                    select ID, Item, 'Para6' from dbo.SplitString(T.Para6, ',')
                   ) as S(ID, Item, Para)
     ) as C
pivot (min(C.Item) for C.Para in (Para1, Para2, Para3, Para4, Para5, Para6)) as P
order by P.SaveName, P.ID

SQL Fiddle

Answer 2

作为使用split function的替代方法，您可以使用recursive common-table-expression拆分数据。

;with cte as
(
  select SaveName,
    cast(left(Para1, charindex(',',Para1+',')-1) as varchar(50)) para1,
    stuff(Para1, 1, charindex(',',Para1+','), '') para1list,
    cast(left(Para2, charindex(',',Para2+',')-1) as varchar(50)) para2,
    stuff(Para2, 1, charindex(',',Para2+','), '') para2list,
    cast(left(Para3, charindex(',',Para3+',')-1) as varchar(50)) para3,
    stuff(Para3, 1, charindex(',',Para3+','), '') para3list,
    cast(left(Para4, charindex(',',Para4+',')-1) as varchar(50)) para4,
    stuff(Para4, 1, charindex(',',Para4+','), '') para4list,
    cast(left(Para5, charindex(',',Para5+',')-1) as varchar(50)) para5,
    stuff(Para5, 1, charindex(',',Para5+','), '') para5list,
    cast(left(Para6, charindex(',',Para6+',')-1) as varchar(50)) para6,
    stuff(Para6, 1, charindex(',',Para6+','), '') para6list
  from yourtable
  union all
  select SaveName,
    cast(left(para1list, charindex(',',para1list+',')-1) as varchar(50)) para1,
    stuff(para1list, 1, charindex(',',para1list+','), '') para1list,
    cast(left(Para2list, charindex(',',Para2list+',')-1) as varchar(50)) para2,
    stuff(Para2list, 1, charindex(',',Para2list+','), '') para2list,
    cast(left(Para3list, charindex(',',Para3list+',')-1) as varchar(50)) para3,
    stuff(Para3list, 1, charindex(',',Para3list+','), '') para3list,
    cast(left(Para4list, charindex(',',Para4list+',')-1) as varchar(50)) para4,
    stuff(Para4list, 1, charindex(',',Para4list+','), '') para4list,
    cast(left(Para5list, charindex(',',Para5list+',')-1) as varchar(50)) para5,
    stuff(Para5list, 1, charindex(',',Para5list+','), '') para5list,
    cast(left(Para6list, charindex(',',Para6list+',')-1) as varchar(50)) para6,
    stuff(Para6list, 1, charindex(',',Para6list+','), '') para6list
  from cte
  where para1list > ''
    or para2list > ''
    or para3list > ''
    or para4list > ''
    or para5list > ''
    or para6list > ''
) 
select SaveName, para1, para2, para3, para4, para5, para6
from cte
order by savename;

请参阅SQL Fiddle with Demo