SQL Server /删除重复项目

Question

我有一个300万记录的表。表看起来像这样：

id   phones 
----------- ----------------- 
0   1234; 5897; 
1   0121; 7875; 5455; 
2   0121; 5455; 7875; 
3   999; 
4   0121; 
5   5455; 0121; 

记录ID为1，2，4 & 5是重复的。我想保留唯一记录最高的id和最长的电话号码。

所以在我的例子中，运行查询后，我的表应该是：

id   phones 
----------- ----------------- 
0   1234; 5897; 
2   0121; 5455; 7875; 
3   999; 

我将如何做到这一点？

注意：电话字符串中没有空格。

Answer 1

这应该是一个很好的起点;

您需要创建2个临时表。

一个将持有ID（列Id），一个将持有手机（列ID，电话）。所以这将是一对多的。

那么你需要做的是在这两个表中插入整个原始表

这样做时，开始排序/比较结果来重建过滤结果。

所以这里是一个演示; （此代码是不是优化但工作）

declare @AllPhones table (id int, phones varchar(max)) 

insert into @AllPhones select 0, '1234; 5897;' 
insert into @AllPhones select 1, '0121; 7875; 5455;' 
insert into @AllPhones select 2, '0121; 5455; 7875;' 
insert into @AllPhones select 3, '999;' 
insert into @AllPhones select 4, '0121;' 
insert into @AllPhones select 5, '5455; 0121;' 
insert into @AllPhones select 6, '222;' 
insert into @AllPhones select 7, '888;' 
insert into @AllPhones select 8, '222; 888;' 
insert into @AllPhones select 9, '888; 222;' 


select * from @AllPhones 

declare @IdPhone table (id int, done bit) 
declare @Phone table (id int, phone varchar(max), insertOrder int) 

insert into @IdPhone 
select id, 0 
from @AllPhones 

declare @Id int 
declare @ConcatPhone varchar(max) 

declare @idx int  
declare @slice varchar(max) 
declare @insertOrder int 

while exists(select * from @IdPhone where done=0) 
begin 
    select top 1 @Id = ap.id 
       , @ConcatPhone = ap.phones 
    from @IdPhone ip inner join @AllPhones ap on ip.id = ap.id 
    where done=0 

    select @idx = 1 
    select @insertOrder = 1  
    if len(@ConcatPhone)> 0 and @ConcatPhone is not null 
    begin 
     while @idx!= 0  
     begin  
      set @idx = charindex(';',@ConcatPhone)  
      if @idx!=0  
       set @slice = left(@ConcatPhone,@idx - 1)  
      else  
       set @slice = @ConcatPhone  

      if(len(@slice)>0) 
       insert into @Phone(Id, phone,insertOrder) values(@Id, rtrim(ltrim(@slice)),@insertOrder)  

      set @ConcatPhone = right(@ConcatPhone,len(@ConcatPhone) - @idx)  
      if len(@ConcatPhone) = 0 break  

      select @insertOrder = @insertOrder+1 
     end 
    end 

    update @IdPhone 
    set done=1 
    where Id = @Id 
end 

declare @UniquePhone table (id int, c int, phone varchar(max),insertOrder int, done int) 

insert into @UniquePhone 
    select p.id 
     , (select top 1 count(pCount.id) from @phone pCount where pCount.id=p.id) as t 
     , p.phone 
     ,p.insertOrder 
     ,0 
    from @phone p 
    group by p.id, p.phone, p.insertOrder 

while exists(select * from @UniquePhone where done=0) 
begin 
    select top 1 @Id = up.id 
    from @UniquePhone up 
    where done=0 
    order by c desc 
      , id desc 

    delete from @UniquePhone 
    where id <> @id and phone in (select phone from @UniquePhone pp where pp.id=@id) 

    print @id 

    update @UniquePhone 
    set done=1 
    where Id = @Id 
end 

select FinalTable.id, 
     ltrim(rtrim(FinalTable.Phones)) As Phones 
from(select distinct up2.id, 
      (select up1.phone + '; ' as [text()] 
      from @UniquePhone up1 
      where up1.id = up2.id 
      order by up1.id, insertOrder 
      for XML PATH ('')) Phones 
    from @UniquePhone up2) [FinalTable]