PIVOT and UNPIVOT in SQL Server

Question

Hi friends I want to know what is PIVOT and UNPIVOT in SQL Server. Thank you.

Satyapriya Nayak · Answer

Hi Vipendra You can use the PIVOT and UNPIVOT relational operators to manipulate a table-valued expression into another table. PIVOT rotates a table-valued expression by turning the unique values from one column in the expression into multiple columns in the output and performs aggregations where necessary on any remaining column values that are desired in the final output. UNPIVOT performs the opposite operation to PIVOT by rotating columns of a table-valued expression into column values. Every PIVOT query involves an aggregation of some type. There are two ways to pivot data: We can convert multiple rows into a single row with repeating groups of columns. We can convert columns on a single row into multiple rows with a generic column and a row type discriminator. Use the following scripts view plain copy to clipboard print ? CREATE TABLE Sales (State CHAR (2) SalesAmt DECIMAL (182)) CREATE TABLE Sales (State CHAR(2) SalesAmt DECIMAL(182)) Insert values view plain copy to clipboard print ? INSERT INTO Sales VALUES ( 'ND' 10000) INSERT INTO Sales VALUES ( 'SD' 30000) INSERT INTO Sales VALUES ( 'TN' 2500.50) INSERT INTO Sales VALUES ( 'OR' 5500.50) INSERT INTO Sales VALUES ( 'VA' 6500.50) INSERT INTO Sales VALUES ( 'SD' 7000) INSERT INTO Sales VALUES ( 'ND' 8000) SELECT * FROM Sales INSERT INTO Sales VALUES ('ND'10000) INSERT INTO Sales VALUES ('SD'30000) INSERT INTO Sales VALUES ('TN'2500.50) INSERT INTO Sales VALUES ('OR'5500.50) INSERT INTO Sales VALUES ('VA'6500.50) INSERT INTO Sales VALUES ('SD'7000) INSERT INTO Sales VALUES ('ND'8000) SELECT * FROM Sales Here is the result set Run the following query view plain copy to clipboard print ? GO SELECT [ND][SD][TN][ OR ][VA] FROM ( SELECT StateSalesAmt FROM Sales) p PIVOT ( SUM (SalesAmt) FOR State IN ([ND][SD][TN][ OR ][VA]) ) AS pvt GO SELECT [ND][SD][TN][OR][VA] FROM (SELECT StateSalesAmt FROM Sales) p PIVOT ( SUM (SalesAmt) FOR State IN ([ND][SD][TN][OR][VA]) ) AS pvt Here is the result set UNPIVOT performs almost the reverse operation of PIVOT  by rotating columns into rows. Use the following scripts view plain copy to clipboard print ? Create the following table  CREATE TABLE StudentMarks( [ Name ] VARCHAR (50) Subject1 VARCHAR (10) Mark1 INT  Subject2 VARCHAR (10) Mark2 INT  Subject3 VARCHAR (10) Mark3 INT ) Create the following table CREATE TABLE StudentMarks( [Name] VARCHAR(50) Subject1 VARCHAR(10) Mark1 INT Subject2 VARCHAR(10) Mark2 INT Subject3 VARCHAR(10) Mark3 INT) Insert values view plain copy to clipboard print ? INSERT INTO StudentMarks([ Name ]Subject1Mark1Subject2Mark2Subject3Mark3) VALUES ( 'AAA'  'Science' 98 'Maths' 89 'English' 76) INSERT INTO StudentMarks([ Name ]Subject1Mark1Subject2Mark2Subject3Mark3) VALUES ( 'XXX'  'Biology' 78 'Chemistry' 85 'Physics' 67) INSERT INTO StudentMarks([ Name ]Subject1Mark1Subject2Mark2) VALUES ( 'YYY'  'Batany' 60 'Zoology' 54) INSERT INTO StudentMarks([ Name ]Subject1Mark1Subject2Mark2) VALUES ( 'ZZZ'  'Maths' 67 'Physics' 78) SELECT * FROM StudentMarks INSERT INTO StudentMarks([Name]Subject1Mark1Subject2Mark2Subject3Mark3) VALUES('AAA''Science'98'Maths'89'English'76) INSERT INTO StudentMarks([Name]Subject1Mark1Subject2Mark2Subject3Mark3) VALUES('XXX''Biology'78'Chemistry'85'Physics'67) INSERT INTO StudentMarks([Name]Subject1Mark1Subject2Mark2) VALUES('YYY''Batany'60'Zoology'54) INSERT INTO StudentMarks([Name]Subject1Mark1Subject2Mark2) VALUES('ZZZ''Maths'67'Physics'78) SELECT * FROM StudentMarks Here is the result set Run the following query view plain copy to clipboard print ? SELECT [ Name ] SubjectName case when Subject= 'Subject1' then Mark1 when Subject= 'Subject2' then Mark2 when Subject= 'Subject3' then Mark3 else NULL end as Marks FROM ( SELECT [ Name ] Subject1Mark1 Subject2Mark2 Subject3Mark3 FROM StudentMarks) p UNPIVOT (SubjectName FOR Subject IN (Subject1 Subject2 Subject3) ) AS unpvt; SELECT [Name] SubjectName case when Subject='Subject1' then Mark1 when Subject='Subject2' then Mark2 when Subject='Subject3' then Mark3 else NULL end as Marks FROM (SELECT [Name] Subject1Mark1 Subject2Mark2 Subject3Mark3 FROM StudentMarks) p UNPIVOT (SubjectName FOR Subject IN (Subject1 Subject2 Subject3) )AS unpvt; Here is the result set Note that UNPIVOT is not the exact reverse of PIVOT. PIVOT performs an aggregation and hence merges possible multiple rows into a single row in the output. UNPIVOT does not reproduce the original table-valued expression result because rows have been merged. Besides NULL values in the input of UNPIVOT disappear in the output whereas there may have been original NULL values in the input before the PIVOT operation. Please refer the below links http://msdn.microsoft.com/en-us/library/ms177410%28v=sql.105%29.aspx http://blog.sqlauthority.com/2008/06/07/sql-server-pivot-and-unpivot-table-examples/ http://www.sql-programmers.com/using-pivot-and-unpivot.aspx Thanks

Muralidharan Deenathayalan · Answer

http://blogs.msdn.com/b/spike/archive/2009/03/03/pivot-tables-in-sql-server-a-simple-sample.aspx http://msdn.microsoft.com/en-us/library/ms177410(v=sql.105).aspx http://blog.sqlauthority.com/2008/06/07/sql-server-pivot-and-unpivot-table-examples/