All geek questions in one place

Need some serious help with the problem of self-join

As you may know, you cannot index a view using self-join. Well, even in fact, even two joins of the same table, even if it is not technically self-join. A few guys from Microsoft came up with a job. But it’s so complicated that I don’t understand it !!!

The solution to the problem is here: http://jmkehayias.blogspot.com/2008/12/creating-indexed-view-with-self-join.html

The view with which I want to apply this work is as follows:

create VIEW vw_lookup_test
WITH SCHEMABINDING
AS
select
count_big(*) as [count_all],
awc_txt,
city_nm,
str_nm,
stru_no,
o.circt_cstdn_nm [owner],
t.circt_cstdn_nm [tech],
dvc.circt_nm,
data_orgtn_yr 
from 
((dbo.dvc 
join dbo.circt 
on dvc.circt_nm = circt.circt_nm) 
join dbo.circt_cstdn o
on circt.circt_cstdn_user_id = o.circt_cstdn_user_id)
join dbo.circt_cstdn t
on dvc.circt_cstdn_user_id = t.circt_cstdn_user_id
group by
awc_txt,
city_nm,
str_nm,
stru_no,
o.circt_cstdn_nm,
t.circt_cstdn_nm,
dvc.circt_nm,
data_orgtn_yr 
go

Any help would be greatly appreciated !!!

Thank you very much in advance!

EDIT: , , . , , - .

alter VIEW vw_lookup_owner_test2
WITH SCHEMABINDING  
AS 
select
count_big(*) as [countAll],
awc_txt,
city_nm,
str_nm,
stru_no,
dvc.circt_nm,
circt_cstdn_nm,
data_orgtn_yr,
dvc.circt_cstdn_user_id
from dbo.dvc 
join dbo.circt
on dvc.circt_nm = circt.circt_nm
join dbo.circt_cstdn o
on circt.circt_cstdn_user_id = o.circt_cstdn_user_id
group by
awc_txt,
city_nm,
str_nm,
stru_no,
dvc.circt_nm,
circt_cstdn_nm,
data_orgtn_yr,
dvc.circt_cstdn_user_id
go


CREATE UNIQUE CLUSTERED INDEX [idx_vw_lookup_owner2_test1] ON [dbo].[vw_lookup_owner_test2] 
(
    [awc_txt] ASC,
    [city_nm] ASC,
    [str_nm] ASC,
    [stru_no] ASC,
    [circt_nm] ASC,
    [circt_cstdn_nm] ASC,
    [data_orgtn_yr] ASC,
    [circt_cstdn_user_id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
GO


create view vw_lookup_dvc_loc
as
select
awc_txt,
city_nm,
str_nm,
stru_no,
circt_nm,
o.circt_cstdn_nm as [owner],
--o.circt_cstdn_user_id,
t.circt_cstdn_nm as tech,
data_orgtn_yr
from vw_lookup_owner_test2 o With (NOEXPAND)
join circt_cstdn t
on o.circt_cstdn_user_id = t.circt_cstdn_user_id
group by
awc_txt,
city_nm,
str_nm,
stru_no,
circt_nm,
o.circt_cstdn_nm,
data_orgtn_yr,
t.circt_cstdn_nm
--o.circt_cstdn_user_id

additon . , ( , ) , .

+3
2

blogpost

  • , 2 dbo.circt_cstdn, -

             owner       tech
rowA     a.nm        b.nm
...

  • , 2 , 2 ( 2 ) , , . , 1.1 1.2 ( )

             name   for
row1.1   nm     owner
row1.2   nm     tech
...

  • . . max , PIVOT ( ), , ,      row1 nm nm ...

,

  • d,

     i
 1
 2


  • SELECT 
     count_big(*) as [count_all], 
     awc_txt, 
     city_nm, 
     str_nm, 
     stru_no, 
     dvc.circt_nm, 
     data_orgtn_yr
FROM  
     dbo.dvc  
     INNER JOIN dbo.circt on dvc.circt_nm = circt.circt_nm
     CROSS JOIN dbo.d  
GROUP BY
     awc_txt, city_nm, str_nm, stru_no, dvc.circt_nm, data_orgtn_yr, d.i

  • , D.i 1, , D.i - 2

    SELECT 
     count_big(*) as [count_all], 
     awc_txt, 
     city_nm, 
     str_nm, 
     stru_no, 
     dvc.circt_nm, 
     data_orgtn_yr,
     Case 
         WHEN d.i = 1 THEN 'Owner'
         WHEN d.i = 2 THEN 'Tech'
     END
FROM  
     dbo.dvc  
     INNER JOIN dbo.circt on dvc.circt_nm = circt.circt_nm
     CROSS JOIN dbo.d 
GROUP BY
     awc_txt, city_nm, str_nm, stru_no, dvc.circt_nm, data_orgtn_yr, 
     Case 
         WHEN d.i = 1 THEN 'Owner'
         WHEN d.i = 2 THEN 'Tech'
     END

  • nm. , circt_cstdn circt, (d.i = 1), dvc, (d.i = 2). . , . , ( circt.circt_cstdn_user_id dvc.circt_cstdn_user_id, WHERE )

    SELECT 
     count_big(*) as [count_all], 
     awc_txt, 
     city_nm, 
     str_nm, 
     stru_no, 
     dvc.circt_nm, 
     data_orgtn_yr,
     Case 
         WHEN d.i = 1 THEN 'Owner'
         WHEN d.i = 2 THEN 'Tech'
     END as PersonType,
     circt_cstdn_nm
FROM  
     dbo.dvc  
     INNER JOIN dbo.circt on dvc.circt_nm = circt.circt_nm
     CROSS JOIN dbo.d 
     INNER JOIN dbo.circt_cstdn on circt_cstdn_user_id = 
          CASE
               WHEN d.i = 1 THEN circt.circt_cstdn_user_id
               WHEN d.i = 2 THEN dvc.circt_cstdn_user_id
          END
GROUP BY
     awc_txt, city_nm, str_nm, stru_no, dvc.circt_nm, data_orgtn_yr, 
     Case 
         WHEN d.i = 1 THEN 'Owner'
         WHEN d.i = 2 THEN 'Tech'
     END,
     circt_cstdn_nm

  • , ,

    create VIEW vw_lookup_test_imed
WITH SCHEMABINDING 
AS
    <<query above>>  
GO

spell to create INDEX

  • PIVOT PersonType Owner and Tech

    SELECT 
     count_all, 
     awc_txt, 
     city_nm, 
     str_nm, 
     stru_no, 
     dvc.circt_nm, 
     data_orgtn_yr,
     [Owner], 
     [Tech] 
FROM 
( 
     SELECT 
          count_all, 
          awc_txt, 
          city_nm, 
          str_nm, 
          stru_no, 
          dvc.circt_nm, 
          data_orgtn_yr,
          PersonType,
          circt_cstdn_nm
     FROM dbo.vw_lookup_test_imed WITH (NOEXPAND) 
) src 
PIVOT 
( 
     MAX(circt_cstdn_nm) 
     FOR PersonType IN ([Owner], [Tech]) 
) pvt

( , ) .

+1

, JOIN- MS Access. . :

select
count_big(*) as [count_all],
awc_txt,
city_nm,
str_nm,
stru_no,
o.circt_cstdn_nm [owner],
t.circt_cstdn_nm [tech],
dvc.circt_nm,
data_orgtn_yr 

-- HERE
from dbo.dvc
join dbo.circt on (dvc.circt_nm = circt.circt_nm) 
join dbo.circt_cstdn o on (circt.circt_cstdn_user_id = o.circt_cstdn_user_id)
join dbo.circt_cstdn t on (dvc.circt_cstdn_user_id = t.circt_cstdn_user_id)

group by
awc_txt,
city_nm,
str_nm,
stru_no,
o.circt_cstdn_nm,
t.circt_cstdn_nm,
dvc.circt_nm,
data_orgtn_yr

SQL Server, Firebird, Oracle, MySQL . "". "" , . "circt_cstdn" "o". "circt_cstdn" "t".

LEFT JOIN INNER JOIN JOIN.

0

Source: https://habr.com/ru/post/1750131/

More articles:


All Articles