Sql group rows with same value, and put that value into header?
I want to group rows with SQL, my result set is following
name size date
data1 123 12/03/2009 data1 124 15/09/2009 data2 333 02/09/2010 data2 323 02/11/2010 data2 673 02/09/2014 data2 444 05/01/2010I开发者_C百科 want to group result set like this one:
data1
123 12/03/2009 124 15/09/2009 data2 333 02/09/2010 323 02/11/2010 673 02/09/2014 444 05/01/2010is it possible to do this with pure SQL?
Cheers.
GROUP BY WITH ROLLUP
(you're not really grouping - so you would actaully GROUP BY
every column)
http://dev.mysql.com/doc/refman/5.0/en/group-by-modifiers.html
http://chiragrdarji.wordpress.com/2008/09/09/group-by-cube-rollup-and-sql-server-2005/
http://databases.about.com/od/sql/l/aacuberollup.htm
http://www.adp-gmbh.ch/ora/sql/group_by/group_by_rollup.html
http://msdn.microsoft.com/en-us/library/bb522495.aspx
Based on Lieven's code:
DECLARE @Table TABLE (
name varchar(32)
,Size integer
,Date datetime
)
INSERT INTO @Table
VALUES ('data1', 123, GETDATE())
INSERT INTO @Table
VALUES ('data1', 124, GETDATE())
INSERT INTO @Table
VALUES ('data2', 333, GETDATE())
INSERT INTO @Table
VALUES ('data2', 323, GETDATE())
INSERT INTO @Table
VALUES ('data2', 673, GETDATE())
INSERT INTO @Table
VALUES ('data2', 444, GETDATE())
SELECT *
FROM (
SELECT *
FROM @Table
GROUP BY NAME
,size
,date
WITH ROLLUP
) AS X
WHERE NAME IS NOT NULL
AND (
(
Size IS NOT NULL
AND Date IS NOT NULL
)
OR (
Size IS NULL
AND date IS NULL
)
)
ORDER BY NAME
,size
,date
Michael Todd is definitly right when he says this should be done on the client side but for the fun of it, this is one option
DECLARE @Table TABLE (name VARCHAR(32), Size INTEGER, Date DATETIME)
INSERT INTO @Table VALUES ('data1', 123, getdate())
INSERT INTO @Table VALUES ('data1', 124, getdate())
INSERT INTO @Table VALUES ('data2', 333, getdate())
INSERT INTO @Table VALUES ('data2', 323, getdate())
INSERT INTO @Table VALUES ('data2', 673, getdate())
INSERT INTO @Table VALUES ('data2', 444, getdate())
INSERT INTO @Table
SELECT DISTINCT name, NULL, NULL
FROM @Table
SELECT
CASE WHEN Size IS NULL THEN Name ELSE NULL END
, Size
, Date
FROM @Table
ORDER BY Name, Size
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.
You can use two queries and then group/format in the application code.
First query
SELECT DISTINCT(name) AS group_name FROM TABLE ORDER BY name LIMIT 5;
Second query
SELECT size, date FROM TABLE WHERE name IN ('comma separated group_name values from firstQueryResult');
Application code
for every row in firstQueryResult{
group_array[group_name] = secondQueryResult;
}
The resulting group_array will be like;
data1
123 12/03/2009
124 15/09/2009
data2
333 02/09/2010
323 02/11/2010
673 02/09/2014
444 05/01/2010
There might be something like:
select name, size, date from
(
-- select only distinct rows, and empty values for size and date (header rows)
select ROWNUM rown, name, '', ''
from T
group by name
order by name
union all
-- select all data (non-header records)
select ROWNUM+1 rown, name, size, date
from T
order by name
)
order by name, rown
Explanation: First select from the union selects the records for the group header. It sorts the results by name. The row number gives the order. Second select from the union selects all the records for the group header. It sorts the results by name, and the row number gives the order. The union put all the information together. ROWNUM+1 for the second select ensures that records for the header (from the first select) are ordered before the detailed records.
Now... what you need to do and I don't recover so much SQL to know how to do it... is to put '' for name when size or date are '', in the main select (with a case/swich operation). Some help is needed here :).
Just as an observation, in the provided SQL, ROWNUM is a special column that provides the row number for a select (see Oracle for example).
The query is displayed just as principle, I am not 100% sure it works.
Update: ... thats a solution sketch. But I still believe this is a formatting problem, and not an SQL problem.
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