How do I group pivot results in SQL? - sql

Question

I have been able to combine results using the pivot function. Been trying various examples on my solution to group these results together. Am I doing this wrong or is it a simple fix?
create table DBE_LOCATION
(
REF int,
STATUS varchar(1)
);
insert into DBE_LOCATION values
(1, 'A'),
(2, 'A');
create table SYS_SCREEN_FIELD
(
REF int,
FIELD_DISPLAY varchar(20),
ORDER_BY int
);
insert into SYS_SCREEN_FIELD values
(1, 'Location Name', 0),
(2, 'Address', 1),
(3, 'Suburb', 2),
(4, 'Postcode', 3),
(5, 'State', 4),
(6, 'Country', 5);
create table DBE_LOCATION_DATA
(
REF int,
FIELD_REF int,
LOCATION_REF int,
VALUE_TEXT_FIELD varchar(MAX)
);
insert into DBE_LOCATION_DATA values
(1, 1, 1, 'New York'),
(2, 1, 2, 'Japan'),
(3, 2, 1, '123 Address St'),
(4, 2, 2, '456 Address St');
Now the final thing would be to show a result set of each Location with the field display as the column name. Something like this if using the above example:
Ref Location Name Address Status
1 New York 123 Address St A
2 Japan 456 Address Ave A
Have got the following working in gathering the data and creating the dynamic columns:
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX)
select #cols = STUFF((SELECT ',' + QUOTENAME(FIELD_DISPLAY)
from SYS_SCREEN_FIELD
group by FIELD_DISPLAY, ORDER_BY
order by ORDER_BY
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set #query = 'SELECT REF, ' + #cols + ', STATUS from
(
select l.REF, l.STATUS,
f.FIELD_DISPLAY,
d.FIELD_REF, d.VALUE_TEXT_FIELD
from DBE_LOCATION l
right join DBE_LOCATION_DATA d
on l.REF = d.LOCATION_REF
inner join SYS_SCREEN_FIELD f
on d.FIELD_REF = f.REF
) x
pivot
(
max(VALUE_TEXT_FIELD)
for FIELD_DISPLAY in (' + #cols + ')
) p'
execute(#query)
Results are not grouped by REF. How is this done?
SQL Fiddle Link

Answer 1

The problem is with the addition of the column FIELD_REF in your subquery. Even though you are not including this column in your final select list, since it is in your subquery the column is used during the grouping of the PIVOT.
You can see the issue if you include it in your final select, you get a result:
| REF | FIELD_REF | LOCATION NAME | ADDRESS | SUBURB | POSTCODE | STATE | COUNTRY | STATUS |
|-----|-----------|---------------|----------------|--------|----------|--------|---------|--------|
| 1 | 1 | Adelaide | (null) | (null) | (null) | (null) | (null) | S |
| 1 | 2 | (null) | 1 Adelaide St | (null) | (null) | (null) | (null) | S |
The FIELD_REF has a value of 1 and 2 for REF=1, when the aggregate and group by are applied, you will return multiple rows.
If you remove this column from your subquery you will get the result that you want:
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX)
select #cols = STUFF((SELECT ',' + QUOTENAME(FIELD_DISPLAY)
from SYS_SCREEN_FIELD
group by FIELD_DISPLAY, ORDER_BY
order by ORDER_BY
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set #query = 'SELECT REF, ' + #cols + ', STATUS from
(
select l.REF, l.STATUS,
f.FIELD_DISPLAY,
d.VALUE_TEXT_FIELD
from DBE_LOCATION l
right join DBE_LOCATION_DATA d
on l.REF = d.LOCATION_REF
inner join SYS_SCREEN_FIELD f
on d.FIELD_REF = f.REF
) x
pivot
(
max(VALUE_TEXT_FIELD)
for FIELD_DISPLAY in (' + #cols + ')
) p'
execute sp_executesql #query;
See SQL Fiddle with Demo. Now your final result is:
| REF | LOCATION NAME | ADDRESS | SUBURB | POSTCODE | STATE | COUNTRY | STATUS |
|-----|---------------|----------------|--------|----------|--------|---------|--------|
| 1 | Adelaide | 1 Adelaide St | (null) | (null) | (null) | (null) | S |
| 2 | Melbourne | 2 Melbourne St | (null) | (null) | (null) | (null) | S |