Sql COALESCE entire rows?

Question

I just learned about COALESCE and I\'m wondering if it\'s possible to COALESCE an entire row of data between two tables? If not, what\'s the best approach to the following r

Answer 1

This should be pretty performant. It uses a CTE to basically build a small table of Customers that have no matching Employee records, and then it simply UNIONs that result with the Employee records

;WITH FilteredCustomers (Id, Name, Email, Etc)
AS
(
    SELECT  Id, Name, Email, Etc
    FROM    tbl_Customers C
            INNER JOIN tbl_PeopleInCompany PIC
            ON C.Id = PIC.Id
            LEFT JOIN tbl_Employees E
            ON C.Id = E.Id
    WHERE   E.Id IS NULL
)

SELECT  Id, Name, Email, Etc
FROM    tbl_Employees E
        INNER JOIN tbl_PeopleInCompany PIC
        ON C.Id = PIC.Id

UNION

SELECT  Id, Name, Email, Etc
FROM    FilteredCustomers

Using the IN Operator can be rather taxing on large queries as it might have to evaluate the subquery for each record being processed.