SQL查询报告

Question

I am working on a aggregate report and I have got so far with the data but I am unsure how to proceed from here. I get by with SQL but my skills are limited

I have the follow in a temp table

ID   Count  Action
2   23      Installed
2   12      Uninstalled
2   36      Unchanged
3   12      Installed
3   25      Unchanged
4   35      Installed
4   25      Unchanged

I want to convert this into this format

ID  Installed   Uninstalled Unchanged
2   23          12          36
3   12          0           36
4   35          0           25

I have no idea where to go or even how to start to achieve this and cannot find anything to point me in the right direction (Im sure its there somewhere)

Any help would be appriciated

Answer 1

It's called a pivot

Here's the documentation about it

The syntax is

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>;

Answer 2

Try this:

SELECT
  ID, 
  MAX(CASE WHEN "Action" = 'Installed' THEN Count END) AS 'Installed',
  MAX(CASE WHEN "Action" = 'Uninstalled ' THEN Count END) AS 'Uninstalled',
  MAX(CASE WHEN "Action" = 'Unchanged' THEN Count END) AS 'Unchanged'
FROM Table
GROUP BY ID;

Or using the SQL Server PIVOT table operator like so:

SELECT *
FROM 
(
   SELECT * FROM table
)t
PIVOT
(
   MAX("Count") FOR "Action" IN([Installed], [Uninstalled], [Unchanged])
) p

SQL Fiddle Demo for both

However, for unknown number of Action s, you will have to select them dynamically like so:

DECLARE @cols AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(Action) 
                    from Table1
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'');

SET @query = 'SELECT ID,  ' + @cols + ' from 
             (
                SELECT * FROM Table1
             ) x
             PIVOT 
             (
                MAX(count)
                FOR action IN (' + @cols + ')
             ) p ';

EXECUTE(@query);

SQL Fiddle Demo(Dynamic Version)

Answer 3

Pivots are good, but very slow at times. Try it without one.

SELECT ID
    , SUM(CASE WHEN [Action] = 'Installed' THEN [Count] ELSE 0 END) AS Installed
    , SUM(CASE WHEN [Action] = 'Uninstalled' THEN [Count] ELSE 0 END) AS Uninstalled
    , SUM(CASE WHEN [Action] = 'Unchanged' THEN [Count] ELSE 0 END) AS Unchanged
FROM <table>
GROUP BY ID