have table 1 and 2, how can I join them and create table 3? Seems neither left join nor union all would do the trick.
Thanks!

Table1

```
Key Var1 Var2

1    A    AA
2    B  
3    C  
4         DD
5         EE

```

Table2

```
Key Var1 Var2
3    C    CC
4    D    DD
5    E    EE
6    F    FF
7    G    GG

```

Table3

```
Key Var1 Var2
1    A    AA
2    B  
3    C    CC
4    D    DD
5    E    EE

```