Month: September 2014

I was recently tasked with finding all the people in our CRM software that lack email addresses, and with around 3000 contacts, there was no way I was going to do it by hand. SQL to the rescue!
There was just one issue, email addresses are stored in a different table to allow each person to have multiple addresses on file. After a bit of digging around, I came up with this:

SELECT
    T.FirstName,
    T.LastName,
    T.CompanyName
FROM (
    SELECT
        CRM.dbo.Companies.CompanyName,
        CRM.dbo.People.FirstName,
        CRM.dbo.People.LastName,
        CRM.dbo.Emails.EmailAddress
    FROM CRM.dbo.People
    LEFT JOIN CRM.dbo.Emails
    ON CRM.dbo.Emails.PersonId = CRM.dbo.People.PersonId
    LEFT JOIN CRM.dbo.Companies
    ON CRM.dbo.Companies.CompanyId = CRM.dbo.People.CompanyId
) AS T
WHERE T.EmailAddress IS NULL

Let’s go through this line-by-line so we can see exactly what it does.

Continue reading Non-matching records in T-SQL One-to-Many Relations