I'm just learning SAS. This is a pretty simple question -- I'm probably overthinking it.

I have a data set called `people_info` and one of the variables is `SocialSecurityNum`. I have another table called `invalid_ssn` with a single variable: unique and invalid `SocialSecurityNum` observations. 

I would like to have a DATA step (or PROC SQL step) that outputs to `invalid_people_info` if the `SocialSecurityNum` of the person (observation) matches one of the values in the `invalid_ssn` table. Otherwise, it will output back to `people_info`. 

What's the best way to do this? 

**Edit: More info, to clarify...**

`people_info` looks like this:

```
name     SocialSecurityNum
joe      123
john     456
mary     876
bob      657

```

`invalid_ssn` looks like this:

```
SocialSecurityNum
456
876

```

What I want is for `people_info` to change (in place) and look like this:

```
name     SocialSecurityNum
joe      123
bob      657

```

and a new table, called `invalid_people_info` to look like this:

```
name     SocialSecurityNum
john     456
mary     876

```