From 17e0d2a77a97419165aac7c0ab944d23ca2e6e65 Mon Sep 17 00:00:00 2001
From: Ken Powers <ken@kenpowers.net>
Date: Tue, 1 Jan 2019 02:02:17 -0500
Subject: [PATCH 1/2] Update Learn-Schema.md

Add `__typename` to the query to show that union types can still be differentiated on the client and add a second example showing common fields being queried in one spot.
---
 site/learn/Learn-Schema.md | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/site/learn/Learn-Schema.md b/site/learn/Learn-Schema.md
index db6cdde821..7e3589d1a1 100644
--- a/site/learn/Learn-Schema.md
+++ b/site/learn/Learn-Schema.md
@@ -311,6 +311,7 @@ In this case, if you query a field that returns the `SearchResult` union type, y
 # { "graphiql": true}
 {
   search(text: "an") {
+    __typename
     ... on Human {
       name
       height
@@ -327,6 +328,31 @@ In this case, if you query a field that returns the `SearchResult` union type, y
 }
 ```
 
+In this case, since `Human` and `Droid` share a common interface (`Character`), you can query their common fields in one place rather than having to repeat the same fields across multiple types:
+
+```graphql
+{
+  search(text: "an") {
+    __typename
+    ... on Character {
+      name
+    }
+    ... on Human {
+      height
+    }
+    ... on Droid {
+      primaryFunction
+    }
+    ... on Starship {
+      name
+      length
+    }
+  }
+}
+```
+
+Note that `name` is still specified on `Starship` because otherwise it wouldn't show up in the results given that `Starship` is not a `Character`!
+
 ### Input types
 
 So far, we've only talked about passing scalar values, like enums or strings, as arguments into a field. But you can also easily pass complex objects. This is particularly valuable in the case of mutations, where you might want to pass in a whole object to be created. In the GraphQL schema language, input types look exactly the same as regular object types, but with the keyword `input` instead of `type`:

From 3b4163c575aa3789df0962144e7fc0b73a090954 Mon Sep 17 00:00:00 2001
From: Ken Powers <ken@kenpowers.net>
Date: Tue, 1 Jan 2019 21:15:44 -0500
Subject: [PATCH 2/2] Add note about the use of `__typename`

---
 site/learn/Learn-Schema.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/site/learn/Learn-Schema.md b/site/learn/Learn-Schema.md
index 7e3589d1a1..40a5b7ced5 100644
--- a/site/learn/Learn-Schema.md
+++ b/site/learn/Learn-Schema.md
@@ -328,7 +328,9 @@ In this case, if you query a field that returns the `SearchResult` union type, y
 }
 ```
 
-In this case, since `Human` and `Droid` share a common interface (`Character`), you can query their common fields in one place rather than having to repeat the same fields across multiple types:
+The `__typename` field resolves to a `String` which lets you differentiate different data types from each other on the client.
+
+Also, in this case, since `Human` and `Droid` share a common interface (`Character`), you can query their common fields in one place rather than having to repeat the same fields across multiple types:
 
 ```graphql
 {