[Solved] SQL Server - How to use one CTE to do multiple queries?

How to optimize this SQL query?

In case you have your own slow SQL query, you can optimize it automatically here.

For the query above, the following recommendations will be helpful as part of the SQL tuning process.
You'll find 3 sections below:

  1. Description of the steps you can take to speed up the query.
  2. The optimal indexes for this query, which you can copy and create in your database.
  3. An automatically re-written query you can copy and execute in your database.
The optimization process and recommendations:
  1. Create Optimal Indexes (modified query below): The recommended indexes are an integral part of this optimization effort and should be created before testing the execution duration of the optimized query.
Optimal indexes for this query:
CREATE INDEX employee_idx_firstname_lastname ON Employee (FirstName,LastName);
CREATE INDEX someothertable_idx_firstname_lastname ON SomeOtherTable (FirstName,LastName);
The optimized query:
WITH CTE AS (SELECT
        Employee.FirstName,
        Employee.LastName,
        count(*) 
    FROM
        Employee 
    GROUP BY
        Employee.FirstName,
        Employee.LastName 
    HAVING
        count(*) > 1) SELECT
        1 
    FROM
        SomeOtherTable AS sot 
    WHERE
        sot.FirstName = cte.FirstName 
        AND sot.LastName = cte.LastName

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* original question posted on StackOverflow here.