Question

我设置了一个跟踪用户帐户更改的表格。

它有ID，UserAccountNo，OldVal，NewVal，ChangeColumnName列。

我的查询设置类似于：

    Select case 
    when ChangeColumnName = 'Address1' then NewVal else '' end as Address1,
    when ChangeColumnName = 'Address2' then NewVal else '' end as Address2,
    when ChangeColumnName = 'City' then NewVal else '' end as City,
    when ChangeColumnName = 'State' then NewVal else '' end as State,
    when ChangeColumnName = 'Zip' then NewVal else '' end as Zip,
    when ChangeColumnName = 'Phone' then NewVal else '' end as Phone
    from table
    Where (Conditions)

如果有人更改了城市，州和邮政编码，则表格中有3个条目。当我运行此查询时，我返回3行。我想将它们全部放在一起，并且无法弄清楚如何。

当我尝试按照其他帖子的建议使用groupby和max（colname）时，它会给出最大的NewVal值，因此我最终会在Phone列中显示电子邮件地址。

在没有改革整个表的情况下，这可以在SQL 2008中完成吗？

Answer 1

我建议您使用pivot命令，使用此脚本并告诉我：

IF OBJECT_ID('_temp') IS NOT NULL DROP TABLE _temp

SELECT *
    INTO _temp
FROM (
        Select 'PostalCode' AS ChangeColumnName, '95100' AS NewValue UNION ALL
        Select 'City' AS ChangeColumnName, 'Argenteuil' AS NewValue UNION ALL
        Select 'LastName' AS ChangeColumnName, 'DAOUI' AS NewValue UNION ALL
        Select 'FirstName' AS ChangeColumnName, 'Youssef' AS NewValue UNION ALL
        Select 'Phone Number' AS ChangeColumnName, '00212 6 60 93 36 12' AS NewValue 
 ) AS Temp

    DECLARE  @v_ListeColonnes           VARCHAR(MAX) = ''
            ,@v_sql                     VARCHAR(MAX) = ''           

    SELECT @v_ListeColonnes         = @v_ListeColonnes + ',' + QUOTENAME(ChangeColumnName)
    FROM _temp

    IF LEN(@v_ListeColonnes) > 1
        BEGIN
            SELECT @v_ListeColonnes = RIGHT(@v_ListeColonnes, LEN(@v_ListeColonnes)-1)
            SET @v_sql  =    'SELECT '+CHAR(13)
                            +'      ' + @v_ListeColonnes + ' '+CHAR(13)
                            +'FROM _temp '+CHAR(13)
                            +'PIVOT (MAX(NewValue) '+CHAR(13)
                            +'  FOR ChangeColumnName in(' + @v_ListeColonnes + ')) as pvt        '+CHAR(13)
            EXEC(@v_sql)
        END

IF OBJECT_ID('_temp') IS NOT NULL DROP TABLE _temp

我希望这会对你有所帮助。

Answer 2

试试这个

create table #t
(
id int,
userAccountNo int,
oldVal varchar(255),
newVal varchar(255),
changeColName varchar(255)
);

insert #t values (1, 1, '123 main st', '123 s. main st.', 'Address1'),
  (2, 1, 'Springville', 'Springfield', 'City'),
  (3, 1, 'Springfield', 'N. Springfield', 'City'),
  (4, 2, '12345', '12346', 'Zip');

with U as (select distinct userAccountNo from #t),
    Address1 as (select userAccountNo, newVal from #t as T1 where changeColName = 'Address1' and id >=ALL
    (select id from #t as T2 where T1.userAccountNo = T2.userAccountNo and T1.changeColName = T2.changeColName)),
    City as (select userAccountNo, newVal from #t as T1 where changeColName = 'City' and id >=ALL
    (select id from #t as T2 where T1.userAccountNo = T2.userAccountNo and T1.changeColName = T2.changeColName)),
    Zip as  (select userAccountNo, newVal from #t as T1 where changeColName = 'Zip' and id >=ALL
    (select id from #t as T2 where T1.userAccountNo = T2.userAccountNo and T1.changeColName = T2.changeColName))
select
U.userAccountNo,
A1.newVal as [Address1],
C.newVal as [City],
Z.newVal as [Zip]
from
U
full outer join Address1 as A1 on U.userAccountNo = A1.userAccountNo
full outer join City as C on U.userAccountNo = C.userAccountNo
full outer join Zip as Z on U.userAccountNo = Z.userAccountNo;

如果它似乎有用，它可以扩展到覆盖你的所有列。

Answer 3

我假设您需要一行一列来进行所有更改，它适用于任意数量的列更改。

<强> SQL FIDDLE TEST

declare @changes as varchar(max)
declare @UserAccountNo int

set @UserAccountNo=1
set @changes=''

select @changes=@changes + ColumnChanged +'-'    
from changes where UserAccountNo=@UserAccountNo

select @UserAccountNo 'UserAccountNo', @changes 'Changes'

SQL将数据合并为单行

3 个答案: