Validate data based on another table

Databases
1

Hello all,
Hoping someone can help me w/ this select.

I have table that hold attribute_value_id(s) for a given attribute_id
attribute_value_id is the PK for the table.

attribute_values table

attribute_value_id attribute_id
1 A
2 A
3 A
4 A
5 B
6 B
7 B
8 c
9 c
10 c

There is another table that holds a user_id, and attribute_id for that user and an attribute_value_id.

user_attributes table

user_id attribute_id attribute_value_id
U1 A 1
U1 B 5
U1 C 8
U2 A 2
U2 B 6
U2 C 9

Since based on the attribute_values table - I know valid values for each attribute_id
How can I check that the user_attributes table has a valid attribute_value_id for the given attribute_id
For example this would not be a valid row
U2 A 6
b/c 6 isn’t a value of attribute A

What I after is a select that I can run on the user_attributes table
that will tell me if the attribute_value_id is not a value for the attribute_id

Thanks
-Rob

2 
SELECT ua.user_id 
     , ua.attribute_id 
     , ua.attribute_value_id
  FROM user_attributes AS ua
LEFT OUTER
  JOIN attribute_values AS a
    ON a.attribute_value_id = ua.attribute_value_id
   AND a.attribute_id       = ua.attribute_id
 WHERE a.attribute_value_id IS NULL

returns all invalid rows in ua table

3

Perfect - exactly what I needed.

Thanks for the help!