SQL Merge Data into Single Row - sql

Question

I have a table set up that tracks changes to a user's account.
It has ID, UserAccountNo, OldVal, NewVal, ChangeColumnName columns.
I have a query set up similar to this:
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)
If someone changes the city, state, and zip, there are 3 entries in the table. When I run this query, I get 3 rows returned. I would like to get them all together in one row, and haven't been able to figure out how.
When I tried using groupby with max(colname) as suggested in other posts, it gives the max NewVal value, so I end up with email addresses in Phone columns.
Is this possible to do in SQL 2008 without reforming the entire table?

Answer 1

Try this
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;
And if it seems to work it can be extended to cover all of your columns.

Answer 2

I suggest that you use pivot command, use this script and let me know :
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
I hope this will help you.

Answer 3

I assumed you need one row and one column for all changes, it works for any number of columns changed.
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'