CUBE, ROLLUP, COMPUTE, COMPUTE BY, GROUPING SETS
The CUBE and ROLLUP operators are useful in generating reports that contain subtotals and totals. There are extensions of the GROUP BY clause.
–> Difference b/w CUBE and ROLLUP:
– CUBE generates a result set that shows aggregates for all combinations of values in the selected columns.
– ROLLUP generates a result set that shows aggregates for a hierarchy of values in the selected columns.
Let’s check this by a simple example:
select 'A' [class], 1 [rollno], 'a' [section], 80 [marks], 'manoj' stuName into #tempTable UNION select 'A', 2, 'a', 70 ,'harish' UNION select 'A', 3, 'a', 80 ,'kanchan' UNION select 'A', 4, 'b', 90 ,'pooja' UNION select 'A', 5, 'b', 90 ,'saurabh' UNION select 'A', 6, 'b', 50 ,'anita' UNION select 'B', 1, 'a', 60 ,'nitin' UNION select 'B', 2, 'a', 50 ,'kamar' UNION select 'B', 3, 'a', 80 ,'dinesh' UNION select 'B', 4, 'b', 90 ,'paras' UNION select 'B', 5, 'b', 50 ,'lalit' UNION select 'B', 6, 'b', 70 ,'hema' select class, rollno, section, marks, stuName from #tempTable
Output:
class rollno section marks stuName
A 1 a 80 manoj
A 2 a 70 harish
A 3 a 80 kanchan
A 4 b 90 pooja
A 5 b 90 saurabh
A 6 b 50 anita
B 1 a 60 nitin
B 2 a 50 kamar
B 3 a 80 dinesh
B 4 b 90 paras
B 5 b 50 lalit
B 6 b 70 hema
–> WITH ROLLUP:
select class, section, sum(marks) [sum] from #tempTable group by class, section with ROLLUP
Output:
class section sum
A a 230
A b 230
A NULL 460 -- 230 + 230 = 460
B a 190
B b 210
B NULL 400 -- 190 + 210 = 400
NULL NULL 860 -- 460 + 400 = 860
–> WITH CUBE:
select class, section, sum(marks) [sum] from #tempTable group by class, section with CUBE
Output: class section sum A a 230 A b 230 A NULL 460 -- 230 + 230 = 460 B a 190 B b 210 B NULL 400 -- 190 + 210 = 400 NULL NULL 860 -- 460 + 400 = 860 NULL a 420 -- 230 + 190 = 420 NULL b 440 -- 230 + 210 = 440
–> COMPUTE & COMPUTE BY: (this feature is no longer supported and discontinued with SQL Server 2012 and next versions)
A COMPUTE BY clause allows you to see both detail and summary rows with one SELECT statement. You can calculate summary values for subgroups, or a summary value for the whole result set.
The COMPUTE clause takes the following information:
– The optional BY keyword. This calculates the specified row aggregate on a per column basis.
– A row aggregate function name. This includes SUM, AVG, MIN, MAX, or COUNT.
– A column upon which to perform the row aggregate function.
select class, section, marks from #tempTable COMPUTE SUM(marks), AVG(marks) select class, section, marks from #tempTable order by class COMPUTE SUM(marks), AVG(marks) by class select class, section, marks from #tempTable order by class, section COMPUTE SUM(marks), AVG(marks) by class, section
Final Cleanup, drop the temp tables:
drop table #tempTable
–> GROUPING SETS:
SQL Server 2008 has a new GROUPING SETS operator which can generate the same result set as that generated by using a simple GROUP BY, ROLLUP, or CUBE operator.
–> Grouping Sets for SQL Server 2008 and above, check here.
–> Grouping Sets equivalent for SQL Server 2005 and below, check here.
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How do you change the label in the output of COMPUTE BY clause? I’d like to change the default label “Sum” to something more meaningful. Thanks.
Hi @Ed, sorry for replying late. Have you figured out this? if not can you try adding “as ” with the sum() in Compute By clause.
~Manoj
Hi Manoj,
Following code is not working for me in sql 2012. Please suggest. Incorrect syntax near COMPUTE.
select class, section, marks
from #tempTable
COMPUTE SUM(marks), AVG(marks)
select class, section, marks
from #tempTable
order by class
COMPUTE SUM(marks), AVG(marks) by class
select class, section, marks
from #tempTable
order by class, section
COMPUTE SUM(marks), AVG(marks) by class, section
@Vinod, I’m sorry but this feature was discontinued after SQL Server 2008 and will not be available in 2012 and next. I’ll update the blog post regarding the same.
Thanks,
Manoj