add example

Author: XVincentX

graph/patterns/alternate-key.md

@@ -39,26 +39,50 @@ In such case, the system SHOULD throw an exception and encourage the user to use
 
 The same user identified via the alternate key SSN, the canonical (primary) key ID using the non-canonical long form with specified key property name, and the canonical short form without key property name
 
-https://graph.microsoft.com/v1.0/users/1a89ade6-9f59-4fea-a139-23f84e3aef66
+1. Get a specific resource through `$filter`:
 
-https://graph.microsoft.com/v1.0/users(ssn='123-45-6789')
+```http
+GET https://graph.microsoft.com/v1.0/users/?$filter=(ssn eq '123-45-6789')
+```
+
+```json
+{
+  "value": [
+    {
+      "givenName": "Bob",
+      "jobTitle": "Retail Manager",
+      "mail": "[email protected]",
+      "mobilePhone": "+1 425 555 0109",
+      "officeLocation": "18/2111",
+      "preferredLanguage": "en-US",
+      "surname": "Vance",
+      "userPrincipalName": "[email protected]",
+      "id": "1a89ade6-9f59-4fea-a139-23f84e3aef66"
+    }
+  ]
+}
+```
 
-https://graph.microsoft.com/v1.0/users(email='[email protected]')
+2. Get a specific resource through the alternate key:
 
-All of the 3 will yield the sare response:
+```http
+GET https://graph.microsoft.com/v1.0/users/1a89ade6-9f59-4fea-a139-23f84e3aef66
+GET https://graph.microsoft.com/v1.0/users(ssn='123-45-6789')
+GET https://graph.microsoft.com/v1.0/users(email='[email protected]')
+```
 
+All of the 3 will yield the sare response:
 
 ```json
 {
-   "givenName": "Bob",
-   "jobTitle": "Retail Manager",
-   "mail": "[email protected]",
-   "mobilePhone": "+1 425 555 0109",
-   "officeLocation": "18/2111",
-   "preferredLanguage": "en-US",
-   "surname": "Vance",
-   "userPrincipalName": "[email protected]",
-   "id": "1a89ade6-9f59-4fea-a139-23f84e3aef66"
+  "givenName": "Bob",
+  "jobTitle": "Retail Manager",
+  "mail": "[email protected]",
+  "mobilePhone": "+1 425 555 0109",
+  "officeLocation": "18/2111",
+  "preferredLanguage": "en-US",
+  "surname": "Vance",
+  "userPrincipalName": "[email protected]",
+  "id": "1a89ade6-9f59-4fea-a139-23f84e3aef66"
 }
 ```
-