SQL Server 2008 View Group By - sql-server

Question

I have created the following view in SQL Server 2008 to create mailing lists for land owners:
SELECT
dbo.parcel.featid,
CAST(mms_db.dbo.TR_Roll_Master.FMT_ROLL_NO AS decimal(11, 3)) AS Roll,
dbo.parcel.survey, mms_db.dbo.Central_Name_Database.NAME AS Owner,
mms_db.dbo.Central_Name_Database.NAME_2 AS Owner2,
mms_db.dbo.Central_Name_Database.BOX_NUM,
mms_db.dbo.Central_Name_Database.APT_NUM,
mms_db.dbo.Central_Name_Database.FMT_STREET AS House_num,
mms_db.dbo.Central_Name_Database.CITY AS Town,
mms_db.dbo.Central_Name_Database.PROV_CD AS Prov,
mms_db.dbo.Central_Name_Database.POST_CD AS Post_code,
mms_db.dbo.TR_Roll_Number_Owners.NAME_CODE
FROM
mms_db.dbo.TR_Roll_Master
INNER JOIN
dbo.parcel ON mms_db.dbo.TR_Roll_Master.ROLL_NO = dbo.parcel.roll_no COLLATE SQL_Latin1_General_CP1_CI_AS
INNER JOIN
mms_db.dbo.TR_Roll_Number_Owners ON mms_db.dbo.TR_Roll_Master.ROLL_NO = mms_db.dbo.TR_Roll_Number_Owners.ROLL_NO
INNER JOIN
mms_db.dbo.Central_Name_Database ON mms_db.dbo.TR_Roll_Number_Owners.NAME_CODE = mms_db.dbo.Central_Name_Database.NAME_CODE
WHERE
(mms_db.dbo.TR_Roll_Master.DEL_ROLL NOT LIKE '%Y%') AND
(mms_db.dbo.TR_Roll_Master.ROLL_NO NOT LIKE 'P%') OR
(mms_db.dbo.TR_Roll_Master.DEL_ROLL IS NULL) AND (mms_db.dbo.TR_Roll_Master.ROLL_NO NOT LIKE 'P%') OR
(mms_db.dbo.TR_Roll_Master.DEL_ROLL NOT LIKE '%I%') AND
(mms_db.dbo.TR_Roll_Master.ROLL_NO NOT LIKE 'P%')
The view works fine however there are often duplicates as many people own more than one piece of land. I would like to group by Name_Code to eliminate the duplicates.
When I add:
Group by mms_db.dbo.TR_Roll_Number_Owners.NAME_CODE
to the end of the query I am returned with the following response:
SQL Execution Error.
Executed SQL statement: SELECT dbo.parcel.featid, CAST(mms_db.dbo.TR_Roll_Master.FMT_ROLL_NO AS decimal(11,3)) AS Roll,
dbo.parcel.survey,
mms_db.dbo.Central_NameDatabase.Name AS Owner,
mms_db.dbo.Central_Name_Database.NAME_2 AS Owner2,
mms_db.dbo.Central_Name_Database.B...
Error Source: .Net SQLClient Data Provider
Error Message: Column 'dbo.parcel.featid' is invalid in the select list
because it is not contained in either an aggregate function or the
GROUP BY clause.
I'm not sure what I need to change to make this work.
--Edit--
As a sample data, here is a condensed sample of what I would like to achieve
Roll Owner Box_Num Town Prov Post_code Name_Code
100 John Smith 50 Somewhere MB R3W 9T7 00478
200 John Smith 50 Somewhere MB R3W 9T7 00478
300 Peter Smith 72 Somewhere MB R3W 9T9 00592
400 John Smith 90 OtherPlace MB R2R 8V7 00682
John Smith has the name code of 00478. He owns both Roll 100 & 200, Peter Smith owns 300 and another person with the name of John Smith owns 400. Based on different Name_Code values I know that the two John Smith's are different people. I would like an output that would list John Smith with Name_Code 00478 1 time only while also listing Peter Smith and the other John Smith. Name_Code is the only value I can use for grouping as the rest could represent different people with the same name.

Answer 1

If you just want to eliminate duplicates, just use DISTINCT and exclude the columns representing other "people on more than one piece of land" from your query viz:
SELECT DISTINCT
NAME_CODE,
{column2},
{column3},
FROM
[MyView]
However, if you wish to perform aggregation of some sort, or show one random of the "people on more than one piece of land" then you will need the GROUP BY. All non-aggregated columns in the select need to appear in the group by:
SELECT
NAME_CODE,
... Other non aggregated fields here
COUNT(featid) AS NumFeatIds,
MIN(Owner2) AS FirstOwner,
... etc (other aggregated columns)
GROUP BY
NAME_CODE,
... All non-aggregated columns in the select.
Edit
To get the table listed in your edit, you would just need to ORDER BY Name_Code
However to get just one row of John Smith #00478, you need to compromise on the non-unique columns by either eliminating them entirely, using GROUP BY and aggregates on the rows, doing a GROUP_CONCAT type hack to e.g. comma separate them, or to pivot the duplicate row columns as extra columns on the one row.
Since you've mentioned GROUP repeatedly, it seems the aggregation route is necessary. John Smith #00478 has 2 properties, hence 2 discrete Roll values. So Roll can't appear in the aggregated result. So instead, you can return e.g. a count of the Rolls, or the MIN or MAX Roll, but not both Rows*. The other columns (Address related) are probably constant for all properties (assuming John Smith 00478 has one address), but unfortunately SqlServer will require you to include them in the GROUP.
I would suggest you try:
SELECT
COUNT(Roll) AS NumPropertiesOwned,
Owner,
Box_Num,
Town,
Prov,
Post_code,
Name_Code
FROM [MyNewView]
GROUP BY
Owner, Box_Num, Town, Prov, Post_code, Name_Code
ORDER BY Name_Code;
i.e. all the non-aggregated columns must be repeated in the GROUP BY
* unless you use the GROUP_CONCAT hack or the pivot route

Answer 2

its telling you what to do:
"Error Message: Column 'dbo.parcel.featid' is invalid in the select list
because it is not contained in either an aggregate function or the
GROUP BY clause."
This means you have to group the other (non-aggregated) fields too.