SQL UNION but fill in NULL value

Question

I have two tables and a section of Table1 looks something like this

EmployeeID	FirstName	LastName	Gender	Age
A100	Bob	Odenkirk	Male	30
A101	Jon	Jones	NULL	36

Table2 looks similar but contains a duplicate entry with some varying amount of missing/available information, i.e.,

EmployeeID	FirstName	LastName	Gender	Age
A101	Jon	Jones	Male	NULL
A103	Angelina	Jolie	Female	40

I'm fairly new to SQL and I initially tried

 SELECT * 
   FROM Table1
  UNION 
 SELECT *
   FROM Table2

But obviously, the A101 row has different NULL values so it doesn't get treated as duplicates and I get:

EmployeeID	FirstName	LastName	Gender	Age
A100	Bob	Odenkirk	Male	30
A101	Jon	Jones	NULL	36
A101	Jon	Jones	Male	NULL
A103	Angelina	Jolie	Female	40

Is there a general way (i.e. if the table is large and not sure which values might be missing from Table1 or Table2) to somehow "fill in" the NULL values and get the following target output:

EmployeeID	FirstName	LastName	Gender	Age
A100	Bob	Odenkirk	Male	36
A101	Jon	Jones	Male	30
A103	Angelina	Jolie	Female	40

Answer 1

Assuming you can never have "competing" values (i.e., both tables either have the same value or one of them has a null), you could union all the two queries, and then group by the EmployeeID and use max to get the present values and ignore nulls:

SELECT   EmployeeID, MAX(FirstName), MAX(LastName), MAX(Gender), MAX(Age)
FROM     (SELECT EmployeeID, FirstName, LastName, Gender, Age
          FROM   Table1
          UNION ALL
          SELECT EmployeeID, FirstName, LastName, Gender, Age
          FROM   Table2) T
GROUP BY EmployeeID