SQL Server row to column (pivot), column to row (unpivot)

explain

have access to PIVOT and UNPIVOT Relational operators change a table valued expression to another table . PIVOT By converting the unique value of one column in the expression to multiple columns in the output , To rotate table valued expressions . PIVOT Run aggregation when you need to aggregate all the remaining column values required for the final output . And PIVOT Reverse operation ,UNPIVOT Rotate the columns of a table valued expression into column values .
PIVOT The syntax provided is more complex than a series of SELECT…CASE The syntax specified in the statement is simpler and more readable .

grammar

SELECT <non-pivoted column>,      [first pivoted column] AS <column name>,      [second pivoted column] AS <column name>,      ...      [last pivoted column] AS <column name>  FROM      (<SELECT query that produces the data>)       AS <alias for the source query>  PIVOT  (      <aggregation function>(<column being aggregated>)  FOR   [<column that contains the values that will become column headers>]       IN ( [first pivoted column], [second pivoted column],      ... [last pivoted column])  ) AS <alias for the pivot table>  <optional ORDER BY clause>;

PIVOT （ Transfer line column ）

create table #person(id int,num int)insert into #person values(1,157)insert into #person values(2,182)insert into #person values(3,175)insert into #person values(4,165)insert into #person values(5,178)select *from #personselect ' height 'as highs ,[1],[2],[3],[4],[5] from (select id,num from #person) s pivot (avg(num)foR id in([1],[2],[3],[4],[5])  ) as p

The original table

id  num1   1572   1823   1754   1655   178

pivot after

highs   1   2   3   4   5 height   157 182 175 165 178

Column turned （unpivot）

CREATE TABLE pvt (VendorID INT, Emp1 INT, Emp2 INT,      Emp3 INT, Emp4 INT, Emp5 INT);  GO  INSERT INTO pvt VALUES (1,4,3,5,4,4);  INSERT INTO pvt VALUES (2,4,1,5,5,5);  INSERT INTO pvt VALUES (3,4,3,5,4,4);  INSERT INTO pvt VALUES (4,4,2,5,5,4);  INSERT INTO pvt VALUES (5,5,1,5,5,5);  GO  select *from pvtSELECT VendorID, Employee, Orders  FROM      (SELECT VendorID, Emp1, Emp2, Emp3, Emp4, Emp5     FROM pvt) p  UNPIVOT     (Orders FOR Employee IN         (Emp1, Emp2, Emp3, Emp4, Emp5)  )AS unpvt;  GO  

The original table

VendorID    Emp1    Emp2    Emp3    Emp4    Emp51   4   3   5   4   42   4   1   5   5   53   4   3   5   4   44   4   2   5   5   45   5   1   5   5   5

unpivot after

VendorID    Employee    Orders1   Emp1    41   Emp2    31   Emp3    51   Emp4    41   Emp5    42   Emp1    42   Emp2    12   Emp3    52   Emp4    52   Emp5    53   Emp1    43   Emp2    33   Emp3    53   Emp4    43   Emp5    44   Emp1    44   Emp2    24   Emp3    54   Emp4    54   Emp5    45   Emp1    55   Emp2    15   Emp3    55   Emp4    55   Emp5    5

author ： Turbid dust

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