Peter Larsson Blog

Patron Saint of Lost Yaks

Alternative approach to calculate most used time interval

In the past I have given the advice to break down all date intervals into the smallest part, most often minutes. Then OP should group by the minute. -- Prepare sample data DECLARE@Data TABLE ( RecID INT IDENTITY(1, 1) PRIMARY KEY CLUSTERED, CreateDate DATETIME, DeleteDate DATETIME ) -- Populate sample data INSERT@Data ( CreateDate, DeleteDate ) SELECT'2009-01-14 22:33', '2009-01-14 22:35' UNION ALL SELECT'2009-01-14 22:33', '2009-01-14 22:33' UNION ALL SELECT'2009-01-14 22:34', '2009-01-14 22:35' UNION ALL SELECT'2009-01-14 22:35', '2009-01-14 22:35' UNION ALL SELECT'2009-01-14 22:35', '2009-01-14 22:36' UNION ALL SELECT'2009-01-14 22:37', '2009-01-14 22:37' UNION ALL SELECT'2009-01-14 22:39', '2009-01-14 22:39' UNION ALL SELECT'2009-01-14 22:38', '2009-01-14 22:38' UNION ALL SELECT'2009-01-14 22:39', '2009-01-14 22:39' UNION ALL SELECT'2009-01-14 22:41', '2009-01-14 22:41' UNION ALL SELECT'2009-01-14 22:43', '2009-01-14 22:44' UNION ALL SELECT'2009-01-14 22:52', '2009-01-14 22:52' UNION ALL SELECT'2009-01-14 22:53', '2009-01-14 22:53' UNION ALL SELECT'2009-01-14 22:53', '2009-01-14 22:53' UNION ALL SELECT'2009-01-14 22:56', '2009-01-14 22:57' UNION ALL SELECT'2009-01-14 22:57', '2009-01-14 22:57' UNION ALL SELECT'2009-01-14 22:58', '2009-01-14 22:58' UNION ALL SELECT'2009-01-14 22:58', '2009-01-14 22:59' UNION ALL SELECT'2009-01-14 22:59', '2009-01-14 22:59' DECLARE@From INT, @To INT SELECT@From = MIN(DATEDIFF(MINUTE, 0, CreateDate)), @To = MAX(DATEDIFF(MINUTE, 0, DeleteDate)) FROM@Data SELECTw. Read more →

Create another nested XML hierarchy

-- Prepare sample data DECLARE@Sample TABLE ( GalaxyID INT, ObjectID VARCHAR(16), ObjectType VARCHAR(5), ObjectTitle VARCHAR(200) ) INSERT@Sample SELECT1, 'T022520001611242', 'Topic', 'Business Strategy' UNION ALL SELECT1, 'T021320001145243', 'Topic', 'Decision Making' UNION ALL SELECT1, 'T8150310322032', 'Topic', 'New Growth' UNION ALL SELECT1, 'T97200019493829', 'Topic', 'Marketing Strategy' UNION ALL SELECT2, 'T1210018575047', 'Topic', 'Strategic Relationships' UNION ALL SELECT2, 'T1027001655860', 'Topic', 'Globalization' UNION ALL SELECT2, 'T95200015582307', 'Topic', 'Strategic Sourcing' UNION ALL SELECT2, 'T021120001714561', 'Topic', 'Business Processes & Architectures' UNION ALL SELECT3, 'T011820001527219', 'Topic', 'Business Models' UNION ALL SELECT3, 'T022520001622334', 'Topic', 'Venture Capital Processes' UNION ALL SELECT3, 'T524200010114538', 'Topic', 'Entrepreneurial Thinking' UNION ALL SELECT3, 'T011820001524538', 'Topic', 'Drivers of Change & Growth' -- Display the XML SELECTs. Read more →

Easy script for calculating weekday or weekend for a date

SELECT d.theDate, DATEDIFF(DAY, '17530101', d.theDate) % 7 / 5 AS IsWeekend, 1 - DATEDIFF(DAY, '17530101', d.theDate) % 7 / 5 AS IsWeekday FROM ( SELECT CAST('20081124' AS SMALLDATETIME) AS theDate UNION ALL SELECT '20081125' UNION ALL SELECT '20081126' UNION ALL SELECT '20081127' UNION ALL SELECT '20081128' UNION ALL SELECT '20081129' UNION ALL SELECT '20081130' )AS d Legacy Comments Uri Dimant 2009-01-14 re: Easy script for calculating weekday or weekend for a date Hi Peter. Read more →

Find popular combos

DECLARE@Sample TABLE ( StudentID INT, Class VARCHAR(20) ) INSERT@Sample SELECT1, 'Maths' UNION ALL SELECT1, 'English' UNION ALL SELECT1, 'Science' UNION ALL SELECT2, 'Maths' UNION ALL SELECT2, 'English' UNION ALL SELECT2, 'Science' UNION ALL SELECT2, 'History' UNION ALL SELECT3, 'English' UNION ALL SELECT3, 'Maths' UNION ALL SELECT3, 'Science' UNION ALL SELECT3, 'RE' UNION ALL SELECT4, 'Science' UNION ALL SELECT4, 'Maths' UNION ALL SELECT4, 'English' UNION ALL SELECT4, 'History' UNION ALL SELECT4, 'French' ;WITHYak(ClassName, ClassPath, Combinations) AS ( SELECT Class, CAST(Class AS VARCHAR(MAX)), CAST(1 AS INT) FROM @Sample GROUP BY Class UNION ALL SELECT s. Read more →

Strange happening

I had a strange scenario today and I can't reproduce it. I changed current database to adventureworks and ran following code DECLARE@SQL NVARCHAR(200) SET@SQL = 'SELECT DB_NAME()' EXECsp_executesql@SQL EXEC (@SQL) The sp_executesql statement returned "master" and exec statement returned "adventureworks". Read more →

Finding streaks in data

A good article about finding streaks in your data is this article by MVP Jeff Smith http://www.sqlteam.com/article/detecting-runs-or-streaks-in-your-data. Also see http://weblogs.sqlteam.com/peterl/archive/2008/05/13/Lightning-fast-collapsed-date-ranges-and-missing-date-ranges.aspx And this is an alternative way to find your streaks Read more →

Easy sorted numeric pivoting with maximum three columns

-- Prepare sample data DECLARE@Sample TABLE ( ID INT, col INT )   INSERT@Sample SELECT0, 1 UNION ALL SELECT0, 1 UNION ALL SELECT0, 2 UNION ALL SELECT1, 1 UNION ALL SELECT1, 2 UNION ALL SELECT1, 3 UNION ALL SELECT2, 5 UNION ALL SELECT2, 5 UNION ALL SELECT2, 5 UNION ALL SELECT3, 6 UNION ALL SELECT3, 6 UNION ALL SELECT5, 8 UNION ALL SELECT5, 9 UNION ALL SELECT4, 7   -- Pivot the source data SELECTID, MIN(col) AS col1, CASE COUNT(*) WHEN 1 THEN NULL WHEN 2 THEN MAX(col) ELSE SUM(col) - MIN(col) - MAX(col) END AS col2, CASE COUNT(*) WHEN 3 THEN MAX(col) ELSE NULL END AS col3 FROM@Sample GROUPBY ID ORDERBY ID Legacy Comments dineshrajan 2010-08-10 re: Easy sorted numeric pivoting with maximum three columns Good Post. Read more →

Bin packaging

With respect to my old algorithm found here http://weblogs.sqlteam.com/peterl/archive/2008/08/12/How-to-sum-up-an-unknown-number-of-records.aspx which is about how to sum up an unknown number of items, I have come up with a new algorithm.   This new algorithm is about finding all possible sums and how many combinations you have of each sum. Read more →

Stripping out all non-numeric characters from a string

DECLARE@Value NVARCHAR(200) SET@Value = 'a+(6aaaa02.......()/)(/)=(#¤NIOU#H¤CÖIÖERFÖNKER)123456789/fffffffffffff' WHILE@Value LIKE '%[^0-9]%' SET @Value = REPLACE(@Value, SUBSTRING(@Value, PATINDEX('%[^0-9]%', @Value), 1), '') SELECT@Value Legacy Comments Uri Dimant 2008-11-12 re: Stripping out all non-numeric characters from a string declare @string varchar(200) Read more →

Getting date or time only from a Datetime value

SELECTGETDATE() AS theFullDateTime, DATEADD(DAY, DATEDIFF(DAY, 0, GETDATE()), 0) AS theDateOnly, DATEADD(DAY, DATEDIFF(DAY, GETDATE(), 0), GETDATE()) AS theTimeOnly SELECTGETDATE() AS theFullDateTime, DATEADD(DAY, DATEDIFF(DAY, '19000101', GETDATE()), '19000101') AS theDateOnly, DATEADD(DAY, DATEDIFF(DAY, GETDATE(), '19000101'), GETDATE()) AS theTimeOnly Legacy Comments Bill Curnow 2008-11-12 re: Getting date or time only from a Datetime value SELECT GETDATE() AS fullDateTime, Read more →

Create nested hierachy XML

-- Prepare sample data DECLARE@Master TABLE ( ID INT, Name VARCHAR(20) ) INSERT@Master SELECT1, 'Peso' UNION ALL SELECT2, 'SQLTeam' UNION ALL SELECT3, 'SQL' DECLARE @Child TABLE ( MasterID INT, ID INT, Value VARCHAR(20) ) INSERT@Child SELECT1, 1, 'Row 1 for Peso' UNION ALL SELECT1, 2, 'Row 2 for Peso' UNION ALL SELECT2, 3, 'Row 1 for SQLTeam' -- Display the XML SELECTePurchaseOrder. Read more →