Getting rid of Duplicate values - Sql Server

Question

I have the below 5 tables -

   CREATE TABLE [dbo].[MSP_EpmProject](
    [ProjectUID] [uniqueidentifier] NOT NULL,
    [ProjectName] [nvarchar](255) NOT NULL,
    [ProjectAuthorName] [nvarchar](255) NULL,
 CONSTRAINT [PK_MSP_EpmProject] PRIMARY KEY CLUSTERED 
([ProjectUID] ASC)) 

CREATE TABLE [dbo].[Project_CI_Mapping](
    [ProjectName] [nvarchar](255) NOT NULL,
    [CI] [nvarchar](100) NOT NULL)

CREATE TABLE [dbo].[ca_owned_resource]( 
    [resource_name] [nvarchar](100) NOT NULL,
    [resource_description] [nvarchar](255) NULL,
    [resource_family] [int] NULL,
    [resource_class] [int] NOT NULL,
    [resource_status] [int] NULL,   
    [resource_tag] [nvarchar](64) NULL)

CREATE TABLE [dbo].[DimTeamProject](
    [ProjectNodeSK] [int] IDENTITY(1,1) NOT NULL,
    [ProjectNodeGUID] [uniqueidentifier] NOT NULL,
    [ProjectNodeName] [nvarchar](256) NULL,
PRIMARY KEY CLUSTERED 
([ProjectNodeSK] ASC))

CREATE TABLE [dbo].[DimIteration](
    [IterationSK] [int] IDENTITY(1,1) NOT NULL,
    [IterationName] [nvarchar](256) NULL,
    [IterationGUID] [nvarchar](256) NOT NULL,   
PRIMARY KEY CLUSTERED 
([IterationSK] ASC))

I have a simple query that tries to get columns from all the tables, but it is returning me duplicate values. Trying INNER JOIN returns me duplicate values & when trying LEFT OUTER JOIN it gives me NULL values for "DimIteration.IterationName".

The query is -

select m.ProjectName,m.ProjectAuthorName "Project Manager", p.CI,c.resource_tag "Alt CI ID", i.IterationName 
from MSP_EpmProject m, Project_CI_Mapping p, ca_owned_resource c, DimTeamProject t, DimIteration i
where i.ProjectGUID = UPPER(CAST(t.ProjectNodeGUID AS NVARCHAR(256)))
and p.CI = c.resource_name
and m.ProjectName = p.ProjectName
order by m.ProjectName,m.ProjectAuthorName, p.CI,c.resource_tag, i.IterationName

Possible Mappings are -

MSP_EpmProject.ProjectName =  Project_CI_Mapping.ProjectName 
Project_CI_Mapping.CI = ca_owned_resource.resource_name
ca_owned_resource.resource_tag = DimTeamProject.ProjectNodeName
DimIteration.ProjectGUID = UPPER(CAST(DimTeamProject.ProjectNodeGUID AS NVARCHAR(256)))

What would be a suitable solution for the same?

Thanks.

Answer 1

You have a CROSS JOIN in your query. If you rewrite it using the newer ANSI-92 syntax (which i would recommend doing anyway, for reasons explained here) you can see where the cross join lies:

select  m.ProjectName,
        m.ProjectAuthorName "Project Manager", 
        p.CI,c.resource_tag "Alt CI ID", 
        i.IterationName 
from    MSP_EpmProject m
        INNER JOIN Project_CI_Mapping p
            ON m.ProjectName = p.ProjectName
        INNER JOIN ca_owned_resource c
            ON p.CI = c.resource_name
        CROSS JOIN DimTeamProject t
        INNER JOIN DimIteration i
            ON i.ProjectGUID = UPPER(CAST(t.ProjectNodeGUID AS NVARCHAR(256)))
order by m.ProjectName,m.ProjectAuthorName, p.CI,c.resource_tag, i.IterationName;

Basically there is nothing to relate DimTeamProject to any of the tables before hand. Based on the fact that you have this

ca_owned_resource.resource_tag = DimTeamProject.ProjectNodeName

as a possible relation, and it doesn't feature in your query at all I would suggest your query needs to be:

select m.ProjectName,m.ProjectAuthorName "Project Manager", p.CI,c.resource_tag "Alt CI ID", i.IterationName 
from MSP_EpmProject m, Project_CI_Mapping p, ca_owned_resource c, DimTeamProject t, DimIteration i
where i.ProjectGUID = UPPER(CAST(t.ProjectNodeGUID AS NVARCHAR(256)))
and p.CI = c.resource_name
and m.ProjectName = p.ProjectName
and c.resource_tag = t.ProjectNodeName -- NEW Clause
order by m.ProjectName,m.ProjectAuthorName, p.CI,c.resource_tag, i.IterationName

However, as I've already said, I'd recommend ANSI 92 explicit joins so your query would become:

SELECT  m.ProjectName,
        m.ProjectAuthorName "Project Manager", 
        p.CI,c.resource_tag "Alt CI ID", 
        i.IterationName 
FROM    MSP_EpmProject m
        INNER JOIN Project_CI_Mapping p
            ON m.ProjectName = p.ProjectName
        INNER JOIN ca_owned_resource c
            ON p.CI = c.resource_name
        INNER JOIN DimTeamProject t
            ON t.ProjectNodeName = c.resource_tag
        INNER JOIN DimIteration i
            ON i.ProjectGUID = UPPER(CAST(t.ProjectNodeGUID AS NVARCHAR(256)))
ORDER BY m.ProjectName,m.ProjectAuthorName, p.CI,c.resource_tag, i.IterationName;

Answer 2

Without studying the question in too much detail, one way to get rid of duplicates is to insert a GROUP BY clause before the ORDER BY, like this:

select m.ProjectName,m.ProjectAuthorName "Project Manager", p.CI,c.resource_tag "Alt CI ID", i.IterationName 
from MSP_EpmProject m, Project_CI_Mapping p, ca_owned_resource c, DimTeamProject t, DimIteration i
where i.ProjectGUID = UPPER(CAST(t.ProjectNodeGUID AS NVARCHAR(256)))
and p.CI = c.resource_name
and m.ProjectName = p.ProjectName
GROUP BY m.ProjectName,m.ProjectAuthorName, p.CI,c.resource_tag, i.IterationName
order by m.ProjectName,m.ProjectAuthorName, p.CI,c.resource_tag, i.IterationName

Another way is to insert DISTINCT after SELECT and before the first column you wish to return.

e.g. SELECT DISTINCT m.ProjectName...