Kayser Kayser - 1 year ago 55
SQL Question

SQL Grouping and counting together

I try to get the grouping elements as column and the count as row elements.


Possible Types = TypeA, TypeB, typeC, typeD

MyTable (date, status, type, count)

2014-06-27,OPEN,typeA, 1
2014-07-01,OPEN,typeA, 1
2014-07-02,IO,typeB, 2
2014-07-02,IO,typeC, 3
2014-07-02,NIO,typeC, 4

The result should look like. (Groupping on date and status)

date,status,typeA_Count, typeB_Count, typeC_Count, typeD_Count

2014-06-27,OPEN,1, 0, 0, 0
2014-07-01,OPEN,1, 0, 0, 0
2014-07-02,IO, 0, 2, 3, 0
2014-07-02,NIO, 0, 0, 4, 0

Answer Source

A simple way is using CASE/GROUP BY to add up the values;

SELECT "date", "status",
  SUM(CASE WHEN "type"='typeA' THEN "count" ELSE 0 END) typeA_count,
  SUM(CASE WHEN "type"='typeB' THEN "count" ELSE 0 END) typeB_count,
  SUM(CASE WHEN "type"='typeC' THEN "count" ELSE 0 END) typeC_count,
  SUM(CASE WHEN "type"='typeD' THEN "count" ELSE 0 END) typeD_count
FROM mytable
GROUP BY "date", "status"
ORDER BY "date", "status"

An Oracle SQLfiddle to test with, although DB2 should run the same without problems.