CODEWITHSUNDEEP
sqlsql-servert-sqlsql-server-2012pivot
HL8
HL8

Reputation: 1419

SQL 2012 - Pivot and Unpivot

I have summarised data in a table which is similar to this:

Customer Year Month No_trans spend  points
1        2015 1     30       400    10
1        2015 2     20       150    5
1        2015 3     10       500    15
2        2015 1     5        100    7

I would like to try and use Pivot/Unpivot to change to this, is it possible?

??????   Customer 2015_1 2015_2 2015_3  
No_trans 1        30     20     10               
Spend    1        400    150    500
Points   1        10     5      15
No_trans 2        5      0      0               
Spend    2        100    0      0
Points   2        7      0      0

Thanks

Upvotes: 0

Views: 205

Answers (1)

Lukasz Szozda
Lukasz Szozda

Reputation: 176189

You could use dynamic SQL to transpose table:

DECLARE @cols NVARCHAR(MAX) = 
                STUFF((SELECT DISTINCT ',' + QUOTENAME(CONCAT([Year], '_', [Month]))
                      FROM #tab
                      FOR XML PATH(''), TYPE
                     ).value('.', 'NVARCHAR(MAX)') 
                     , 1, 1, '');

DECLARE @query NVARCHAR(MAX) = 
FORMATMESSAGE(
N'SELECT col_name, customer, %s
FROM (SELECT [year_month] = CONCAT([Year], ''_'', [Month]),
             Customer, No_Trans, spend, points
      FROM #tab) AS sub
UNPIVOT
(
    val FOR col_name  IN (No_trans, spend, points)
) AS unpvt
PIVOT
(
    MAX(val) FOR [year_month] IN (%s)
) AS pvt
ORDER BY customer, col_name;', @cols, @cols); 

EXEC [dbo].[sp_executesql] @query;

LiveDemo

Output:

╔══════════╦══════════╦════════╦════════╦════════╗
║   col    ║ customer ║ 2015_1 ║ 2015_2 ║ 2015_3 ║
╠══════════╬══════════╬════════╬════════╬════════╣
║ No_Trans ║        1 ║     30 ║     20 ║     10 ║
║ points   ║        1 ║     10 ║      5 ║     15 ║
║ spend    ║        1 ║    400 ║    150 ║    500 ║
║ No_Trans ║        2 ║      5 ║        ║        ║
║ points   ║        2 ║      7 ║        ║        ║
║ spend    ║        2 ║    100 ║        ║        ║
╚══════════╩══════════╩════════╩════════╩════════╝

If you want zeros at missing position you could use ISNULL/COALESCE. Be aware that not every datatatype could be replaced by 0 (int)

LiveDemo2

EDIT:

FORMATMESSAGE is fancy way to replace %s with string. It could be easily changed by simple REPLACE:

 DECLARE @query NVARCHAR(MAX) = 
 N'SELECT col1, col2, <placeholder>
   FROM ...
   ...
   PIVOT( MAX(col) IN col2 IN (<placeholder>)
   ...';

 SET @query = REPLACE(@query, '<placeholder', @cols);

 -- for debug
 PRINT @query;

How it works:

  1. Generate [year_month] column in subquery
  2. UNPIVOT data (columns to row)
  3. PIVOT result (rows to columns)
  4. Wrap it with dynamic-SQL to allow generate columns without knowing [year_month] in advance.

Upvotes: 1

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