I want to group rows with SQL, my result set is following
name size date
data1 123 12/03/2009
data1 &nb
Shaping the data ahead of time simplifies things for the application developer, especially if all they're doing is displaying a static report with no interactive editing, sorting, or paging --a common enough occurrence.
Lieven's solution (selecting the columns distinctively while inserting nulls for other columns, then checking for the nulls of the other columns) is the only solution here that actually works. Kind of.
data1 NULL NULL
NULL 123 2011-05-24 19:42:29.577
NULL 124 2011-05-24 19:42:29.577
data2 NULL NULL
NULL 323 2011-05-24 19:42:29.577
NULL 333 2011-05-24 19:42:29.577
NULL 444 2011-05-24 19:42:29.577
NULL 673 2011-05-24 19:42:29.577
--unless the column you're nullalizing already has nulls, in which case we're back to square 0. Add one more row.
INSERT INTO @Table VALUES ('data2', NULL, getdate())
Now run the query again. Bummer dude.
data1 NULL NULL
NULL 123 2011-05-24 19:53:36.437
NULL 124 2011-05-24 19:53:36.437
data2 NULL NULL
data2 NULL 2011-05-24 19:53:36.440
NULL 323 2011-05-24 19:53:36.440
NULL 333 2011-05-24 19:53:36.440
NULL 444 2011-05-24 19:53:36.440
Roux's proposed ROLLUP solution doesn't work at all, at least not in SQL Server. Actually, it makes things more worserer.
data1 NULL NULL
data1 NULL NULL
data1 NULL NULL
data1 123 2011-05-24 20:16:26.693
data1 124 2011-05-24 20:16:26.693
data2 NULL NULL
data2 NULL NULL
data2 NULL NULL
data2 323 2011-05-24 20:16:26.693
data2 333 2011-05-24 20:16:26.693
data2 444 2011-05-24 20:16:26.693
data2 673 2011-05-24 20:16:26.693
Pitiș' ROWNUM solution may work in Oracle (I haven't tried it and there appears to a missing beginning parentheses), but the equivalent SQL Server code using ROW_NUMBER() OVER definitely taint working no good neither --about as well as my grammer and speling.
SELECT
ROW_NUMBER() OVER(ORDER BY [name]) AS [rown]
, name
, ''
, ''
FROM @Table
GROUP BY name
UNION ALL
SELECT ROW_NUMBER() OVER(ORDER BY [name]) + 1 AS [rown] , name, size, date
FROM @Table
produces
data1 NULL NULL
data1 NULL NULL
data1 NULL NULL
data1 123 2011-05-24 20:16:26.693
data1 124 2011-05-24 20:16:26.693
data2 NULL NULL
data2 NULL NULL
data2 NULL NULL
data2 323 2011-05-24 20:16:26.693
data2 333 2011-05-24 20:16:26.693
data2 444 2011-05-24 20:16:26.693
data2 673 2011-05-24 20:16:26.693
As a software professional your job is to ensure billions of 1s and 0s line up at the right place, in the right order, at the right time. You know the details, often times down to an individual bit, are important.
A half vast answer is worse than no answer at all because it wastes everyone's time. So... no offense intended because intentions are good, but please at least test your "solution" before posting it as a "solution".
I would be perfect if I weren't so darned humble. And even I test.