From 6f110182a73d9d9c87b24d8f535795a1037100a4 Mon Sep 17 00:00:00 2001
From: "abby.huang" <78209557+abby-cyber@users.noreply.github.com>
Date: Tue, 17 Jan 2023 18:20:30 +0800
Subject: [PATCH] change-returned-`UnknownProp`-to-`NULL` (#2493)

---
 .../6.cheatsheet-for-ngql-command.md          |  2 +-
 .../7.general-query-statements/3.go.md        |  8 ++---
 .../8.clauses-and-options/limit.md            | 14 ++++----
 .../8.clauses-and-options/sample.md           | 34 +++++++++----------
 4 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/docs-2.0/2.quick-start/6.cheatsheet-for-ngql-command.md b/docs-2.0/2.quick-start/6.cheatsheet-for-ngql-command.md
index 31cd463fa3..f88544a659 100644
--- a/docs-2.0/2.quick-start/6.cheatsheet-for-ngql-command.md
+++ b/docs-2.0/2.quick-start/6.cheatsheet-for-ngql-command.md
@@ -253,7 +253,7 @@
   | `GO FROM "player102" OVER serve YIELD dst(edge)`                             | 返回 player102 所属队伍。                                 |
   | `GO 2 STEPS FROM "player102" OVER follow YIELD dst(edge)`                    | 返回距离 player102 两跳的朋友。                           |
   | `GO FROM "player100", "player102" OVER serve WHERE properties(edge).start_year > 1995 YIELD DISTINCT properties($$).name AS team_name, properties(edge).start_year AS start_year, properties($^).name AS player_name` | 添加过滤条件。                                          |
-  | `GO FROM "player100" OVER follow, serve YIELD properties(edge).degree, properties(edge).start_year` | 遍历多个 Edge type。属性没有值时，会显示`UNKNOWN_PROP`。 |
+  | `GO FROM "player100" OVER follow, serve YIELD properties(edge).degree, properties(edge).start_year` | 遍历多个 Edge type。属性没有值时，会显示`NULL`。 |
   | `GO FROM "player100" OVER follow REVERSELY YIELD src(edge) AS destination` | 返回 player100 入方向的邻居点。                           |
   | `GO FROM "player100" OVER follow REVERSELY YIELD src(edge) AS id | GO FROM $-.id OVER serve WHERE properties($^).age > 20 YIELD properties($^).name AS FriendOf, properties($$).name AS Team` | 查询 player100 的朋友和朋友所属队伍。                     |
   | `GO FROM "player102" OVER follow YIELD dst(edge) AS both`    | 返回 player102 所有邻居点。                               |
diff --git a/docs-2.0/3.ngql-guide/7.general-query-statements/3.go.md b/docs-2.0/3.ngql-guide/7.general-query-statements/3.go.md
index cc62d504d5..bd07d2308c 100644
--- a/docs-2.0/3.ngql-guide/7.general-query-statements/3.go.md
+++ b/docs-2.0/3.ngql-guide/7.general-query-statements/3.go.md
@@ -105,15 +105,15 @@ nebula> GO FROM "player100", "player102" OVER serve \
 ```
 
 ```ngql
-# 遍历多个 Edge type。属性没有值时，会显示 UNKNOWN_PROP。
+# 遍历多个 Edge type。属性没有值时，会显示`NULL`。
 nebula> GO FROM "player100" OVER follow, serve \
         YIELD properties(edge).degree, properties(edge).start_year;
 +-------------------------+-----------------------------+
 | properties(EDGE).degree | properties(EDGE).start_year |
 +-------------------------+-----------------------------+
-| 95                      | UNKNOWN_PROP                |
-| 95                      | UNKNOWN_PROP                |
-| UNKNOWN_PROP            | 1997                        |
+| 95                      | __NULL__                    |
+| 95                      | __NULL__                    |
+| __NULL__                | 1997                        |
 +-------------------------+-----------------------------+
 ```
 
diff --git a/docs-2.0/3.ngql-guide/8.clauses-and-options/limit.md b/docs-2.0/3.ngql-guide/8.clauses-and-options/limit.md
index 25ab83e7e2..571ab8ef3e 100644
--- a/docs-2.0/3.ngql-guide/8.clauses-and-options/limit.md
+++ b/docs-2.0/3.ngql-guide/8.clauses-and-options/limit.md
@@ -80,13 +80,13 @@ nebula> GO 3 STEPS FROM "player100" \
         OVER * \
         YIELD properties($$).name AS NAME, properties($$).age AS Age \
         LIMIT [3,3,3];
-+-----------------+--------------+
-| NAME            | Age          |
-+-----------------+--------------+
-| "Spurs"         | UNKNOWN_PROP |
-| "Tony Parker"   | 36           |
-| "Manu Ginobili" | 41           |
-+-----------------+--------------+
++-----------------+----------+
+| NAME            | Age      |
++-----------------+----------+
+| "Tony Parker"   | 36       |
+| "Manu Ginobili" | 41       |
+| "Spurs"         | __NULL__ |
++-----------------+----------+
 
 nebula> GO 3 STEPS FROM "player102" OVER * BIDIRECT\
         YIELD dst(edge) \
diff --git a/docs-2.0/3.ngql-guide/8.clauses-and-options/sample.md b/docs-2.0/3.ngql-guide/8.clauses-and-options/sample.md
index b2ff5f0d23..ec031b4420 100644
--- a/docs-2.0/3.ngql-guide/8.clauses-and-options/sample.md
+++ b/docs-2.0/3.ngql-guide/8.clauses-and-options/sample.md
@@ -23,26 +23,26 @@ nebula> GO 3 STEPS FROM "player100" \
         OVER * \
         YIELD properties($$).name AS NAME, properties($$).age AS Age \
         SAMPLE [1,2,3];
-+-----------------+--------------+
-| NAME            | Age          |
-+-----------------+--------------+
-| "Spurs"         | UNKNOWN_PROP |
-| "Tony Parker"   | 36           |
-| "Manu Ginobili" | 41           |
-+-----------------+--------------+
++-----------------+----------+
+| NAME            | Age      |
++-----------------+----------+
+| "Tony Parker"   | 36       |
+| "Manu Ginobili" | 41       |
+| "Spurs"         | __NULL__ |
++-----------------+----------+
 
 nebula> GO 1 TO 3 STEPS FROM "player100" \
         OVER * \
         YIELD properties($$).name AS NAME, properties($$).age AS Age \
         SAMPLE [2,2,2];
-+---------------------+-----+
-| NAME                | Age |
-+---------------------+-----+
-| "Manu Ginobili"     | 41  |
-| "Tony Parker"       | 36  |
-| "Tim Duncan"        | 42  |
-| "LaMarcus Aldridge" | 33  |
-| "Tony Parker"       | 36  |
-| "Tim Duncan"        | 42  |
-+---------------------+-----+
++-----------------+----------+
+| NAME            | Age      |
++-----------------+----------+
+| "Manu Ginobili" | 41       |
+| "Spurs"         | __NULL__ |
+| "Tim Duncan"    | 42       |
+| "Spurs"         | __NULL__ |
+| "Manu Ginobili" | 41       |
+| "Spurs"         | __NULL__ |
++-----------------+----------+
 ```