How to Query Active Directory (AD) from SQL Server

There can be a scenario where you will want to query Active Directory, directly from your stored procedure. This can be achieved by creating a linked server to your target Active Directory and then querying it through OPENQUERY functionality. Following is an example to achieve this:

Step 1: Add Linked Server for Active Directory

sp_addlinkedserver 'ADSI', 'Active Directory Service Interfaces', 'ADSDSOObject', 'adsdatasource'

Step 2: Query the Active Directory

SELECT * FROM OpenQuery
(
ADSI,   --Name of the linked server for Active directory, created in step 1
'SELECT title, displayName, sAMAccountName, givenName, telephoneNumber, facsimileTelephoneNumber, sn   --Fields you want to retreive
FROM ''LDAP://DC=TestDomain''    --Name of your Active Directory Domain
where objectClass = ''User'''         --Type of objects you want to query e.g. User, Person etc...
)

NOTE: The order in which columns will return will be exactly reversed of what you mentioned in your query. For example, in above query we have mentioned 
title, displayName…….,facsimileTelephoneNumber, sn but the resultset will return as
sn,facsimileTelephoneNumber……,displayName,title.
There is no reason of this behaviour and it is just how Active Directory OLEDB Provider works.

Search all columns of all tables for a particular value

Several times I have came across with the question that how can I search all columns of all tables in a SQL Server database for a particular value. Unfortunately, you can not perform this query directly by any already provided system table or object. 

There are some fundamental points to remember:

 

1. You have to iterate the list of tables and for each table you have to iterate each column and perform an exist query against it. 
2. You will need three types of queries due to the data types i.e. string, number and date and time.

I have found an excellent article here which provides a good explanation along with the necessary sql script. I would recommend every reader to read this article.