Query Logic Help

  • Hello,

    I have 4 different data sources I would like to compare. Basically I have a list of users from our Intranet, Active Directory, Phone System, and Cell Phone provider.

    What I would like to do is compare all data to see if data is accurate across the board. One challege I have is their is no ID to tie each data source together. I plan on matching the best I can based on FirstName and LastName.

    How can I create a query that will show all records for each file in one report and tie them together if the last and first names are identical? Do I need to do a UNION for this or is there a better way?

  • If you're data is still in the source systems, I would suggest ETL'ing them into tables in a single database. Then you could easily do a SQL query like this:

    select *

    from AD_info a

    left join cell_info b on a.firstname = b.firstname and a.lastname = b.lastname

    left join ...

    Hopefully you don't have too many John Smiths...

  • SQL Hamster (7/22/2015)


    If you're data is still in the source systems, I would suggest ETL'ing them into tables in a single database. Then you could easily do a SQL query like this:

    select *

    from AD_info a

    left join cell_info b on a.firstname = b.firstname and a.lastname = b.lastname

    left join ...

    Hopefully you don't have too many John Smiths...

    Assuming they all end up in the same database, using a LEFT JOIN is not necessarily going to provide what's needed, as a full comparison needs to see ALL values, and not just those that come from any one given system. FULL OUTER JOIN is needed here, like this:

    SELECT COALESCE(AD.LastName, INET.LastName, PH.LastName, CELL.LastName) AS LastName,

    COALESCE(AD.FirstName, INET.FirstName, PH.FirstName, CELL.FirstName) AS FirstName,

    CASE WHEN AD.LastName IS NULL THEN 0 ELSE 1 END AS AD,

    CASE WHEN PH.LastName IS NULL THEN 0 ELSE 1 END AS PH,

    CASE WHEN INET.LastName IS NULL THEN 0 ELSE 1 END AS INET,

    CASE WHEN CELL.LastName IS NULL THEN 0 ELSE 1 END AS CELL,

    FROM ADInfo AS AD

    FULL OUTER JOIN IntranetInfo AS INET

    ON AD.LastName = INET.LastName

    AND AD.FirstName = INET.FirstName

    FULL OUTER JOIN PhoneInfo AS PH

    ON AD.LastName = PH.LastName

    AND AD.FirstName = PH.FirstName

    FULL OUTER JOIN CellProviderInfo AS CELL

    ON AD.LastName = CELL.LastName

    AND AD.FirstName = CELL.FirstName

    ORDER BY COALESCE(AD.LastName, INET.LastName, PH.LastName, CELL.LastName) AS LastName,

    COALESCE(AD.FirstName, INET.FirstName, PH.FirstName, CELL.FirstName) AS FirstName

    Steve (aka sgmunson) 🙂 🙂 🙂
    Rent Servers for Income (picks and shovels strategy)

  • thank you for for your time and help!!!

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