please help to write the query

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please help to write the query

Author

Topic

deniskodua
Starting Member

1 Post

Posted - 2013-12-08 : 07:06:15

There is a table with information about
how many partners at what stage is the

need to get another column to the table
"Number of partners in the previous step"
(the previous stage is a stage for the previous row in this table)

I made ??it through the left join, but I need to do without the left join
and without a nested subquery in select

Is this possible?

example


DECLARE @t TABLE
(
	id INT PRIMARY KEY IDENTITY(1,1),
	stage_code NVARCHAR(MAX),
	stage_level INT,
	partner_id INT
)


INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('simple_application', 0, 11)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('simple_application',0, 13)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('simple_application',0, 14)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('simple_application',0, 15)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('extended_application',0, 16)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('extended_application',0, 18)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('extended_application',0, 12)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('extended_application',0, 17)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('finance_stage',1, 11)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('finance_stage',1, 12)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('legal_stage',2, 11)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('legal_stage',2, 12)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('registration_ip',3, 11)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('registration_ip',3, 12)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('acting_partner',4, 11)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('acting_partner',4, 12)
INSERT INTO @t(stage_code, stage_level, partner_id) VALUES('acting_partner', 4, 13)

select * from @t



SELECT res.stage_code,
		ISNULL(res.stage_level, 0) AS current_level,
		 ISNULL(res.partners_count, 0) AS on_current_stage_partners_count,
		  ISNULL(self.stage_level, 0) AS previous_level,
		   ISNULL(self.partners_count, 0) AS on_previous_level_partners_count
 FROM
 (SELECT stage_code,
		  stage_level,
		   COUNT(partner_id) AS partners_count
		 FROM @t
		  GROUP BY stage_code, stage_level) res 
LEFT JOIN
(SELECT stage_level,
		  COUNT(partner_id)	AS partners_count
   FROM @t GROUP BY stage_level) self ON(res.stage_level - 1 = self.stage_level)

SwePeso
Patron Saint of Lost Yaks

30421 Posts

Posted - 2013-12-08 : 09:29:28

You should consider using a recursive CTE.

Microsoft SQL Server MVP, MCT, MCSE, MCSA, MCP, MCITP, MCTS, MCDBA

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