fixed some issues (#1098)

docs-2.0/3.ngql-guide/9.space-statements/4.describe-space.md

@@ -16,9 +16,9 @@ The `DESCRIBE SPACE` statement is different from the `SHOW SPACES` statement. Fo
 
 ```ngql
 nebula> DESCRIBE SPACE basketballplayer;
-+----+--------------------+------------------+----------------+---------+------------+--------------------+-------------+-----------+---------+
-| ID | Name               | Partition Number | Replica Factor | Charset | Collate    | Vid Type           | Atomic Edge | Group     | Comment |
-+----+--------------------+------------------+----------------+---------+------------+--------------------+-------------+-----------+---------+
-| 1  | "basketballplayer" | 10               | 1              | "utf8"  | "utf8_bin" | "FIXED_STRING(32)" | false       | "default" |         |
-+----+--------------------+------------------+----------------+---------+------------+--------------------+-------------+-----------+---------+
++----+--------------------+------------------+----------------+---------+------------+--------------------+-------------+-------------------------------+---------+
+| ID | Name               | Partition Number | Replica Factor | Charset | Collate    | Vid Type           | Atomic Edge | Zones                         | Comment |
++----+--------------------+------------------+----------------+---------+------------+--------------------+-------------+-------------------------------+---------+
+| 1  | "basketballplayer" | 10               | 1              | "utf8"  | "utf8_bin" | "FIXED_STRING(32)" | false       | "default_zone_127.0.0.1_9779" |         |
++----+--------------------+------------------+----------------+---------+------------+--------------------+-------------+-------------------------------+---------+
 ```

docs-2.0/4.deployment-and-installation/3.upgrade-nebula-graph/upgrade-nebula-graph-to-latest.md

@@ -53,6 +53,16 @@ To upgrade Nebula Graph from historical versions to {{nebula.release}}:
 
   A few configuration parameters have been changed. For more information, see the release notes and configuration docs.
 
+- nGQL compatibility
+
+  The nGQL syntax is partially incompatible:
+
+  - Disable the `YIELD` clause to return custom variables.
+
+  - The `YIELD` clause is required in the `FETCH`, `GO`, `LOOKUP`, `FIND PATH` and `GET SUBGRAPH` statements.
+
+  - It is required to specify a tag to query properties of a vertex in a `MATCH` statement. For example, from `return v.name` to `return v.player.name`.
+
 !!! caution
 
     There may be other undiscovered influences. Before the upgrade, we recommend that you read the release notes and user manual carefully, and keep an eye on the [posts](https://discuss.nebula-graph.io/) on the forum and [issues](https://github.com/vesoft-inc/nebula/issues) on Github.