I need help creating the below results. I thought of a sql pivot but I don't know how to use it. Looked at a few examples and cannot come up with a solution. Any other ideas on how to accomplish this is also welcome. Status columns must be dynamically generated.
Have three tables, assets, assettypes, assetstatus
Table: assets assetid int assettag varchar(25) assettype int assetstatus int Table: assettypes id int typename varchar(20) (ex: Desktop, Laptop, Server, etc.) Table: assetstatus id int statusname varchar(20) (ex: Deployed, Inventory, Shipped, etc.)
Desired results:
AssetType Total Deployed Inventory Shipped ... ----------------------------------------------------------- Desktop 100 75 20 5 ... Laptop 75 56 19 1 ... Server 60 50 10 0 ...
Some Data:
assets table: 1,hol1234,1,1 2,hol1233,1,2 3,hol3421,2,3 4,svr1234,3,1 assettypes table: 1,Desktop 2,Laptop 3,Server assetstatus table: 1,Deployed 2,Inventory 3,Shipped
This type of transformation is called a pivot. You did not specify what database you are using so I will provide a answers for SQL Server and MySQL.
SQL Server: If you are using SQL Server 2005+ you can implement the PIVOT
function.
If you have a known number of values that you want to convert to columns then you can hard-code the query.
select typename, total, Deployed, Inventory, shipped
from
(
select count(*) over(partition by t.typename) total,
s.statusname,
t.typename
from assets a
inner join assettypes t
on a.assettype = t.id
inner join assetstatus s
on a.assetstatus = s.id
) d
pivot
(
count(statusname)
for statusname in (Deployed, Inventory, shipped)
) piv;
See SQL Fiddle with Demo.
But if you have an unknown number of status
values, then you will need to use dynamic sql to generate the list of columns at run-time.
DECLARE @cols AS NVARCHAR(MAX),
@query AS NVARCHAR(MAX)
select @cols = STUFF((SELECT distinct ',' + QUOTENAME(statusname)
from assetstatus
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set @query = 'SELECT typename, total,' + @cols + ' from
(
select count(*) over(partition by t.typename) total,
s.statusname,
t.typename
from assets a
inner join assettypes t
on a.assettype = t.id
inner join assetstatus s
on a.assetstatus = s.id
) x
pivot
(
count(statusname)
for statusname in (' + @cols + ')
) p '
execute(@query)
This can also be written using an aggregate function with a case expression:
select typename,
total,
sum(case when statusname ='Deployed' then 1 else 0 end) Deployed,
sum(case when statusname ='Inventory' then 1 else 0 end) Inventory,
sum(case when statusname ='Shipped' then 1 else 0 end) Shipped
from
(
select count(*) over(partition by t.typename) total,
s.statusname,
t.typename
from assets a
inner join assettypes t
on a.assettype = t.id
inner join assetstatus s
on a.assetstatus = s.id
) d
group by typename, total
MySQL: This database does not have a pivot function so you will have to use the aggregate function and a CASE
expression. It also does not have windowing functions, so you will have to alter the query slightly to the following:
select typename,
total,
sum(case when statusname ='Deployed' then 1 else 0 end) Deployed,
sum(case when statusname ='Inventory' then 1 else 0 end) Inventory,
sum(case when statusname ='Shipped' then 1 else 0 end) Shipped
from
(
select t.typename,
(select count(*)
from assets a1
where a1.assettype = t.id
group by a1.assettype) total,
s.statusname
from assets a
inner join assettypes t
on a.assettype = t.id
inner join assetstatus s
on a.assetstatus = s.id
) d
group by typename, total;
Then if you need a dynamic solution in MySQL, you will have to use a prepared statement to generate the sql string to execute:
SET @sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'sum(CASE WHEN statusname = ''',
statusname,
''' THEN 1 else 0 END) AS `',
statusname, '`'
)
) INTO @sql
FROM assetstatus;
SET @sql
= CONCAT('SELECT typename,
total, ', @sql, '
from
(
select t.typename,
(select count(*)
from assets a1
where a1.assettype = t.id
group by a1.assettype) total,
s.statusname
from assets a
inner join assettypes t
on a.assettype = t.id
inner join assetstatus s
on a.assetstatus = s.id
) d
group by typename, total');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
See SQL Fiddle with Demo.
The result is the same for all queries in both databases:
| TYPENAME | TOTAL | DEPLOYED | INVENTORY | SHIPPED |
-----------------------------------------------------
| Desktop | 2 | 1 | 1 | 0 |
| Laptop | 1 | 0 | 0 | 1 |
| Server | 1 | 1 | 0 | 0 |