CrossTab Query / Pivot Table in MS SQL? - sql

Question

I have a table that has the follow data structure:
terminal | load_time_mns | vehicle
_________________________________________
Terminal 1 | 3 | AA
Terminal 2 | 10 | AF
Terminal 1 | 1 | BF
Terminal 6 | 3 | QRS
Terminal 6 | 1.4 | AA
Terminal 3 | 2.5 | OP
I am trying to get an interval breakdown of load time from each terminal.For example, for the above table, I am trying to create a breakdown that looks like the following:
terminal | [0-1 mns] | [1-2 mns] | [2-3 mns] |
_______________________________________________________________
Terminal 1 | 0 | 1 | 1
_______________________________________________________________
Terminal 2 | 0 | 0 | 0
_______________________________________________________________
Terminal 3 | 0 | 0 | 1
_______________________________________________________________
Terminal 6 | 0 | 1 | 1
After a bit of Googling, it looks like I should be focusing on the pivot() function and crosstab queries. I am reading up on those two, but am still not quite able to get

Answer 1

Something like this might help:
Query 1:
SELECT
terminal,
count(CASE WHEN load_time_mns >= 0 AND load_time_mns < 1 THEN 1 END) [0-1 mns],
count(CASE WHEN load_time_mns >= 1 AND load_time_mns < 2 THEN 1 END) [1-2 mns],
count(CASE WHEN load_time_mns >= 2 AND load_time_mns < 3 THEN 1 END) [2-3 mns]
FROM t
GROUP BY terminal
Results:
| TERMINAL | 0-1 MNS | 1-2 MNS | 2-3 MNS |
|------------|---------|---------|---------|
| Terminal 1 | 0 | 1 | 0 |
| Terminal 2 | 0 | 0 | 0 |
| Terminal 3 | 0 | 0 | 1 |
| Terminal 6 | 0 | 1 | 0 |
Fiddle here.
Note that in your example you did not include 1 in the [0-1] range but you did include 3 in the [0-3] range, which seems not right.

Answer 2

You can use a bit of dynamic SQL to extend this to the complete result set. Create a table called intervals to store the intervals:
Create Table ex (
terminal varchar(10),
load_time_mns decimal(10, 2),
vehicle varchar(3)
);
Insert Into ex values
('Terminal 1', 3, 'AA'),
('Terminal 2', 10, 'AF'),
('Terminal 1', 1, 'BF'),
('Terminal 6', 3, 'QRS'),
('Terminal 6', 1.4, 'AA'),
('Terminal 3', 2.5, 'OP');
Create Table intervals (
min_mns decimal(10, 2),
max_mns decimal(10, 2),
column_name sysname
);
declare #i int = 0
while #i <= 20
begin
insert into intervals values (
#i, #i + 1, convert(varchar, #i) + '-' + convert(varchar, #i + 1)
);
set #i += 1;
end
while #i <= 420
begin
insert into intervals values (
#i, #i + 5, convert(varchar, #i) + '-' + convert(varchar, #i + 5)
);
set #i += 5;
end
You can then use a cursor to build up the complete SQL
declare
#sql nvarchar(max) = N'select terminal',
#lo int, #hi int, #col sysname;
declare pivot_cursor cursor local fast_forward for
select
min_mns, max_mns, column_name
from
intervals
order by
min_mns;
open pivot_cursor;
fetch next from pivot_cursor into #lo, #hi, #col;
while ##fetch_status = 0
begin
set #sql += ', sum(case when load_time_mns >= ' + convert(varchar, #lo)
+ ' and load_time_mns < ' + convert(varchar, #hi)
+ ' then 1 else 0 end) as [' + #col + ']';
fetch next from pivot_cursor into #lo, #hi, #col;
end
close pivot_cursor;
deallocate pivot_cursor;
Set #sql += ' from ex group by Terminal order by terminal';
exec sp_executesql #sql;
Example SQLFiddle

Answer 3

DECLARE #t TABLE ( terminal VARCHAR(10), load_time_mns DECIMAL(5,2), vehicle VARCHAR(3))
INSERT INTO #t ( terminal, load_time_mns, vehicle )
VALUES
('Terminal 1' , 3 , 'AA'),
('Terminal 2' , 10 , 'AF'),
('Terminal 2' , 20 , 'AF'),
('Terminal 1' , 1 , 'BF'),
('Terminal 1' , 25 , 'BF'),
('Terminal 6' , 3 , 'QRS'),
('Terminal 6' , 1.4 , 'AA'),
('Terminal 3' , 2.5 , 'OP')
;WITH intervals AS
(
SELECT m = 0, n = 1
UNION ALL
SELECT CASE WHEN m < 20 THEN m+1 ELSE m+5 END, CASE WHEN n < 20 THEN n+1 ELSE n+5 END
FROM intervals
WHERE n<420
)
SELECT terminal, load_time_mns, vehicle,
interval = CAST(m AS VARCHAR(10)) + '-' + CAST(n AS VARCHAR(10)), m
INTO ##tmp
FROM intervals i
LEFT JOIN #t t
ON t.load_time_mns >= i.m
AND t.load_time_mns < i.n
OPTION (MAXRECURSION 0)
DECLARE #cols VARCHAR(MAX) =
STUFF(CAST((SELECT ',' + QUOTENAME(interval)
FROM (
SELECT DISTINCT interval, m
FROM ##tmp
) t
ORDER BY m
FOR XML PATH(''), TYPE
) AS VARCHAR(MAX)),1,1,'')
DECLARE #sql VARCHAR(MAX) = '
SELECT terminal, ' + #cols + '
FROM (
SELECT terminal, vehicle, interval
FROM ##tmp
) t
PIVOT (
COUNT(vehicle)
FOR interval IN (' + #cols + ')
) p
'
EXEC(#sql)
DROP TABLE ##tmp