From 39ee41294098feede21b816654f27d0dbf0c3089 Mon Sep 17 00:00:00 2001
From: cooper-lzy <78672629+cooper-lzy@users.noreply.github.com>
Date: Tue, 8 Feb 2022 15:07:56 +0800
Subject: [PATCH] update docs (#1077)

---
 docs-2.0/2.quick-start/4.nebula-graph-crud.md | 37 ++++++++++++-------
 .../2.quick-start/6.cheatsheet-for-ngql.md    |  2 +-
 .../1.nGQL-overview/1.overview.md             | 14 +++++--
 3 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/docs-2.0/2.quick-start/4.nebula-graph-crud.md b/docs-2.0/2.quick-start/4.nebula-graph-crud.md
index 4e99138e3cd..f1a4379ca3d 100644
--- a/docs-2.0/2.quick-start/4.nebula-graph-crud.md
+++ b/docs-2.0/2.quick-start/4.nebula-graph-crud.md
@@ -167,9 +167,14 @@ From the **Status** column of the table in the returned results, you can see tha
 ### nGQL syntax
 
 ```ngql
-CREATE {TAG | EDGE} {<tag_name> | <edge_type>}(<property_name> <data_type>
-[, <property_name> <data_type> ...])
-[COMMENT = '<comment>'];
+CREATE {TAG | EDGE} [IF NOT EXISTS] {<tag_name> | <edge_type_name>}
+    (
+      <prop_name> <data_type> [NULL | NOT NULL] [DEFAULT <default_value>] [COMMENT '<comment>']
+      [{, <prop_name> <data_type> [NULL | NOT NULL] [DEFAULT <default_value>] [COMMENT '<comment>']} ...] 
+    )
+    [TTL_DURATION = <ttl_duration>]
+    [TTL_COL = <prop_name>]
+    [COMMENT = '<comment>'];
 ```
 
 For more information on parameters, see [CREATE TAG](../3.ngql-guide/10.tag-statements/1.create-tag.md) and [CREATE EDGE](../3.ngql-guide/11.edge-type-statements/1.create-edge.md).
@@ -205,7 +210,7 @@ You can use the `INSERT` statement to insert vertices or edges based on existing
 
     ```ngql
     INSERT VERTEX [IF NOT EXISTS] [tag_props, [tag_props] ...]
-    VALUES VID: ([prop_value_list])
+    VALUES <vid>: ([prop_value_list])
 
     tag_props:
       tag_name ([prop_name_list])
@@ -217,14 +222,18 @@ You can use the `INSERT` statement to insert vertices or edges based on existing
        [prop_value [, prop_value] ...]   
     ```
 
-    `VID` is short for Vertex ID. A `VID` must be a unique string value in a graph space. For details, see [INSERT VERTEX](../3.ngql-guide/12.vertex-statements/1.insert-vertex.md).
+    `vid` is short for Vertex ID. A `vid` must be a unique string value in a graph space. For details, see [INSERT VERTEX](../3.ngql-guide/12.vertex-statements/1.insert-vertex.md).
 
 * Insert edges:
 
     ```ngql
-    INSERT EDGE [IF NOT EXISTS] <edge_type> (<property_name>[, <property_name>...])
-    VALUES <src_vid> -> <dst_vid>[@<rank>] : (<property_value>[, <property_value>...])
-    [, <src_vid> -> <dst_vid>[@<rank>] : (<property_name>[, <property_name>...]), ...];
+    INSERT EDGE [IF NOT EXISTS] <edge_type> ( <prop_name_list> ) VALUES 
+    <src_vid> -> <dst_vid>[@<rank>] : ( <prop_value_list> )
+    [, <src_vid> -> <dst_vid>[@<rank>] : ( <prop_value_list> ), ...];
+    <prop_name_list> ::=
+    [ <prop_name> [, <prop_name> ] ...]
+    <prop_value_list> ::=
+    [ <prop_value> [, <prop_value> ] ...]
     ```
 
    For more information on parameters, see [INSERT EDGE](../3.ngql-guide/13.edge-statements/1.insert-edge.md).
@@ -272,10 +281,10 @@ You can use the `INSERT` statement to insert vertices or edges based on existing
     ```ngql
     GO [[<M> TO] <N> STEPS ] FROM <vertex_list>
     OVER <edge_type_list> [{REVERSELY | BIDIRECT}]
-    [ WHERE <conditions> ]
-    YIELD [DISTINCT] <return_list>
-    [{SAMPLE <sample_list> | LIMIT <limit_list>}]
-    [| GROUP BY {col_name | expr | position} YIELD <col_name>]
+    [ WHERE <conditions> ]
+    YIELD [DISTINCT] <return_list>
+    [{ SAMPLE <sample_list> | <limit_by_list_clause> }]
+    [| GROUP BY {<col_name> | expression> | <position>} YIELD <col_name>]
     [| ORDER BY <expression> [{ASC | DESC}]]
     [| LIMIT [<offset>,] <number_rows>];
     ```
@@ -303,12 +312,14 @@ You can use the `INSERT` statement to insert vertices or edges based on existing
     LOOKUP ON {<vertex_tag> | <edge_type>}
     [WHERE <expression> [AND <expression> ...]]
     YIELD <return_list> [AS <alias>];
+    <return_list>
+        <prop_name> [AS <col_alias>] [, <prop_name> [AS <prop_alias>] ...];
     ```
 
 * `MATCH`
 
     ```nGQL
-    MATCH <pattern> [<WHERE clause>] RETURN <output>;
+    MATCH <pattern> [<clause_1>] RETURN <output> [<clause_2>];
     ```
 
 ### Examples of `GO` statement
diff --git a/docs-2.0/2.quick-start/6.cheatsheet-for-ngql.md b/docs-2.0/2.quick-start/6.cheatsheet-for-ngql.md
index 41149652dbf..cb5c1c1f92a 100644
--- a/docs-2.0/2.quick-start/6.cheatsheet-for-ngql.md
+++ b/docs-2.0/2.quick-start/6.cheatsheet-for-ngql.md
@@ -411,7 +411,7 @@
 
 | Statement                                                         | Syntax                                                         | Example                                                         | Description                                                         |
 | ------------------------------------------------------------ | ------------------------------------------------------------ | ------------------------------------------------------------ | ------------------------------------------------------------ |
-| [INSERT VERTEX](../3.ngql-guide/12.vertex-statements/1.insert-vertex.md) | `INSERT VERTEX [IF NOT EXISTS] [tag_props, [tag_props] ...] VALUES VID: ([prop_value_list])` | `INSERT VERTEX t2 (name, age) VALUES "13":("n3", 12), "14":("n4", 8)` | Inserts one or more vertices into a graph space in Nebula Graph.           |
+| [INSERT VERTEX](../3.ngql-guide/12.vertex-statements/1.insert-vertex.md) | `INSERT VERTEX [IF NOT EXISTS] [tag_props, [tag_props] ...] VALUES <vid>: ([prop_value_list])` | `INSERT VERTEX t2 (name, age) VALUES "13":("n3", 12), "14":("n4", 8)` | Inserts one or more vertices into a graph space in Nebula Graph.           |
 | [DELETE VERTEX](../3.ngql-guide/12.vertex-statements/4.delete-vertex.md) | `DELETE VERTEX <vid> [, <vid> ...]`                          | `DELETE VERTEX "team1"`                                      | Deletes vertices and the related incoming and outgoing edges of the vertices.                             |
 | [UPDATE VERTEX](../3.ngql-guide/12.vertex-statements/2.update-vertex.md) | `UPDATE VERTEX ON <tag_name> <vid> SET <update_prop> [WHEN <condition>] [YIELD <output>]` | `UPDATE VERTEX ON player "player101" SET age = age + 2 `     | Updates properties on tags of a vertex.                                        |
 | [UPSERT VERTEX](../3.ngql-guide/12.vertex-statements/3.upsert-vertex.md) | `UPSERT VERTEX ON <tag> <vid> SET <update_prop> [WHEN <condition>] [YIELD <output>]` | `UPSERT VERTEX ON player "player667" SET age = 31`           | The `UPSERT` statement is a combination of `UPDATE` and `INSERT`. You can use `UPSERT VERTEX` to update the properties of a vertex if it exists or insert a new vertex if it does not exist. |
diff --git a/docs-2.0/3.ngql-guide/1.nGQL-overview/1.overview.md b/docs-2.0/3.ngql-guide/1.nGQL-overview/1.overview.md
index 64f2473efab..43552b110e2 100644
--- a/docs-2.0/3.ngql-guide/1.nGQL-overview/1.overview.md
+++ b/docs-2.0/3.ngql-guide/1.nGQL-overview/1.overview.md
@@ -40,17 +40,23 @@ For details of the symbols in nGQL syntax, see the following table:
 |  Token | Meaning  |
 |  ----  | ----  |
 | < >    | name of a syntactic element |
-| ::=    | formula that defines an element |
+| :      | formula that defines an element |
 | [ ]    | optional elements |
 | { }    | explicitly specified elements |
 |  \|    | complete alternative elements |
 | ...    | may be repeated any number of times |
 
-For example, create vertices or edges in nGQL syntax:
+For example, create vertices in nGQL syntax:
 
 ```ngql
-CREATE {TAG | EDGE} {<tag_name> | <edge_type>}(<property_name> <data_type>
-[, <property_name> <data_type> ...]);
+INSERT VERTEX [IF NOT EXISTS] [tag_props, [tag_props] ...]
+VALUES <vid>: ([prop_value_list])
+tag_props:
+  tag_name ([prop_name_list])
+prop_name_list:
+   [prop_name [, prop_name] ...]
+prop_value_list:
+   [prop_value [, prop_value] ...]  
 ```
 
 Example statement: