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yield for full doc #1070

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8 changes: 4 additions & 4 deletions docs-2.0/1.introduction/3.nebula-graph-architecture/3.graph-service.md
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Expand Up @@ -20,7 +20,7 @@ Graph 服务主要负责处理查询请求，包括解析查询语句、校验

Parser 模块收到请求后，通过 Flex（词法分析工具）和 Bison（语法分析工具）生成的词法语法解析器，将语句转换为抽象语法树（AST），在语法解析阶段会拦截不符合语法规则的语句。

例如`GO FROM "Tim" OVER like WHERE like.likeness > 8.0 YIELD like._dst`语句转换的 AST 如下。
例如`GO FROM "Tim" OVER like WHERE properties(edge).likeness > 8.0 YIELD dst(edge)`语句转换的 AST 如下。

![AST](https://docs-cdn.nebula-graph.com.cn/docs-2.0/1.introduction/2.nebula-graph-architecture/parser-ast-tree.png)

Expand All @@ -38,7 +38,7 @@ Validator 模块对生成的 AST 进行语义校验，主要包括：

校验引用的变量是否存在或者引用的属性是否属于变量。

例如语句`$var = GO FROM "Tim" OVER like YIELD like._dst AS ID; GO FROM $var.ID OVER serve YIELD serve._dst`，Validator 模块首先会检查变量 `var` 是否定义，其次再检查属性 `ID` 是否属于变量 `var`。
例如语句`$var = GO FROM "Tim" OVER like YIELD dst(edge) AS ID; GO FROM $var.ID OVER serve YIELD dst(edge)`，Validator 模块首先会检查变量 `var` 是否定义，其次再检查属性 `ID` 是否属于变量 `var`。

- 校验类型推断

Expand All @@ -50,13 +50,13 @@ Validator 模块对生成的 AST 进行语义校验，主要包括：

查询语句中包含 `*` 时，校验子句时需要将 `*` 涉及的Schema都进行校验。

例如语句`GO FROM "Tim" OVER * YIELD like._dst, like.likeness, serve._dst`，校验`OVER`子句时需要校验所有的 Edge type，如果 Edge type 包含 `like`和`serve`，该语句会展开为`GO FROM "Tim" OVER like,serve YIELD like._dst, like.likeness, serve._dst`。
例如语句`GO FROM "Tim" OVER * YIELD dst(edge), properties(edge).likeness, dst(edge)`，校验`OVER`子句时需要校验所有的 Edge type，如果 Edge type 包含 `like`和`serve`，该语句会展开为`GO FROM "Tim" OVER like,serve YIELD dst(edge), properties(edge).likeness, dst(edge)`。

- 校验输入输出

校验管道符（|）前后的一致性。

例如语句`GO FROM "Tim" OVER like YIELD like._dst AS ID | GO FROM $-.ID OVER serve YIELD serve._dst`，Validator 模块会校验 `$-.ID` 在管道符左侧是否已经定义。
例如语句`GO FROM "Tim" OVER like YIELD dst(edge) AS ID | GO FROM $-.ID OVER serve YIELD dst(edge)`，Validator 模块会校验 `$-.ID` 在管道符左侧是否已经定义。

校验完成后，Validator 模块还会生成一个默认可执行，但是未进行优化的执行计划，存储在目录 `src/planner` 内。

Expand Down
2 changes: 1 addition & 1 deletion docs-2.0/14.client/4.nebula-java-client.md
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Expand Up @@ -101,7 +101,7 @@ try {
ResultSet resp = session.execute(insertEdges);

// query
String query = "GO FROM \"Bob\" OVER like " + "YIELD $$.person.name, $$.person.age, like.likeness";
String query = "GO FROM \"Bob\" OVER like " + "YIELD properties($$).name, properties($$).age, properties(edge).likeness";
ResultSet resp = session.execute(query);
printResult(resp);
}finally {
Expand Down
85 changes: 47 additions & 38 deletions docs-2.0/2.quick-start/4.nebula-graph-crud.md
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Expand Up @@ -269,34 +269,37 @@ Execution succeeded (time spent 5858/6870 us)

```ngql
GO [[<M> TO] <N> STEPS ] FROM <vertex_list>
OVER <edge_type_list> [REVERSELY] [BIDIRECT]
[WHERE <expression> [AND | OR expression ...])]
YIELD [DISTINCT] <return_list>;
OVER <edge_type_list> [{REVERSELY | BIDIRECT}]
[ WHERE <conditions> ]
[YIELD [DISTINCT] <return_list>]
[| GROUP BY {col_name | expr | position} YIELD <col_name>]
[| ORDER BY <expression> [{ASC | DESC}]]
[| LIMIT [<offset_value>,] <number_rows>];
```

- `FETCH`

- 查询Tag属性

```ngql
FETCH PROP ON {<tag_name> | <tag_name_list> | *} <vid_list>
[YIELD [DISTINCT] <return_list>];
FETCH PROP ON {<tag_name>[, tag_name ...] | *}
<vid> [, vid ...]
[YIELD <return_list> [AS <alias>]];
```

- 查询边属性

```ngql
FETCH PROP ON <edge_type> <src_vid> -> <dst_vid>[@<rank>]
[, <src_vid> -> <dst_vid> ...]
[YIELD [DISTINCT] <return_list>];
FETCH PROP ON <edge_type> <src_vid> -> <dst_vid>[@<rank>] [, <src_vid> -> <dst_vid> ...]
[YIELD <output>];
```

- `LOOKUP`

```ngql
LOOKUP ON {<tag_name> | <edge_type>}
WHERE <expression> [AND expression ...])]
[YIELD <return_list>];
LOOKUP ON {<vertex_tag> | <edge_type>}
[WHERE <expression> [AND <expression> ...]]
[YIELD <return_list> [AS <alias>]];
```

- `MATCH`
Expand Down Expand Up @@ -324,14 +327,15 @@ Execution succeeded (time spent 5858/6870 us)
- 从VID为`player100`的球员开始，沿着边`follow`查找年龄大于或等于35岁的球员，并返回他们的姓名和年龄，同时重命名对应的列。

```ngql
nebula> GO FROM "player100" OVER follow WHERE $$.player.age >= 35 \
YIELD $$.player.name AS Teammate, $$.player.age AS Age;
+---------------+-----+
| Teammate | Age |
+---------------+-----+
| "Tony Parker" | 36 |
+---------------+-----+
Got 1 rows (time spent 8206/9335 us)
nebula> GO FROM "player100" OVER follow WHERE properties($$).age >= 35 \
YIELD properties($$).name AS Teammate, properties($$).age AS Age;
+-----------------+-----+
| Teammate | Age |
+-----------------+-----+
| "Tony Parker" | 36 |
+-----------------+-----+
| "Manu Ginobili" | 41 |
+-----------------+-----+
```

|子句/符号|说明|
Expand All @@ -345,15 +349,18 @@ Execution succeeded (time spent 5858/6870 us)
- 使用管道符

```ngql
nebula> GO FROM "player100" OVER follow YIELD follow._dst AS id | \
GO FROM $-.id OVER serve YIELD $$.team.name AS Team, \
$^.player.name AS Player;
+-----------+---------------+
| Team | Player |
+-----------+---------------+
| "Nuggets" | "Tony Parker" |
+-----------+---------------+
Got 1 rows (time spent 5055/8203 us)
nebula> GO FROM "player100" OVER follow YIELD dst(edge) AS id | \
GO FROM $-.id OVER serve YIELD properties($$).name AS Team, \
properties($^).name AS Player;
+-----------+-----------------+
| Team | Player |
+-----------+-----------------+
| "Spurs" | "Tony Parker" |
+-----------+-----------------+
| "Hornets" | "Tony Parker" |
+-----------+-----------------+
| "Spurs" | "Manu Ginobili" |
+-----------+-----------------+
```

|子句/符号|说明|
Expand All @@ -369,15 +376,18 @@ Execution succeeded (time spent 5858/6870 us)
当复合语句作为一个整体提交给服务器时，其中的临时变量会在语句结束时被释放。

```ngql
nebula> $var = GO FROM "player100" OVER follow YIELD follow._dst AS id; \
GO FROM $var.id OVER serve YIELD $$.team.name AS Team, \
$^.player.name AS Player;
+---------+-------------+
| Team | Player |
+---------+-------------+
| Nuggets | Tony Parker |
+---------+-------------+
Got 1 rows (time spent 3103/3711 us)
nebula> $var = GO FROM "player100" OVER follow YIELD dst(edge) AS id; \
GO FROM $var.id OVER serve YIELD properties($$).name AS Team, \
properties($^).name AS Player;
+-----------+-----------------+
| Team | Player |
+-----------+-----------------+
| "Spurs" | "Tony Parker" |
+-----------+-----------------+
| "Hornets" | "Tony Parker" |
+-----------+-----------------+
| "Spurs" | "Manu Ginobili" |
+-----------+-----------------+
```

### `FETCH`语句示例
Expand All @@ -391,7 +401,6 @@ nebula> FETCH PROP ON player "player100";
+----------------------------------------------------+
| ("player100" :player{age: 42, name: "Tim Duncan"}) |
+----------------------------------------------------+
Got 1 rows (time spent 2006/2406 us)
```

!!! Note
Expand Down
12 changes: 6 additions & 6 deletions docs-2.0/3.ngql-guide/1.nGQL-overview/1.overview.md
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Expand Up @@ -156,18 +156,18 @@ Feature: Comparison of where clause
When profiling query:
"""
GO FROM "player100" OVER follow
WHERE follow.degree IN [v IN [95,99] WHERE v > 0]
YIELD follow._dst, follow.degree
WHERE properties(edge).degree IN [v IN [95,99] WHERE v > 0]
YIELD dst(edge), properties(edge).degree
"""
Then the result should be, in any order:
| follow._dst | follow.degree |
| "player101" | 95 |
| "player125" | 95 |
And the execution plan should be:
| id | name | dependencies | operator info |
| 0 | Project | 1 | |
| 1 | GetNeighbors | 2 | {"filter": "(follow.degree IN [v IN [95,99] WHERE (v>0)])"} |
| 2 | Start | | |
| id | name | dependencies | operator info |
| 0 | Project | 1 | |
| 1 | GetNeighbors | 2 | {"filter": "(properties(edge).degree IN [v IN [95,99] WHERE (v>0)])"} |
| 2 | Start | | |
```

示例中的关键字说明如下。
Expand Down
34 changes: 17 additions & 17 deletions docs-2.0/3.ngql-guide/1.nGQL-overview/ngql-style-guide.md
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Expand Up @@ -13,35 +13,35 @@ nGQL没有严格的构建格式要求，但根据恰当而统一的风格创建n
不推荐：

```ngql
GO FROM "player100" OVER follow REVERSELY YIELD follow._dst AS id;
GO FROM "player100" OVER follow REVERSELY YIELD src(edge) AS id;
```

推荐：

```ngql
GO FROM "player100" \
OVER follow REVERSELY \
YIELD follow._dst AS id;
YIELD src(edge) AS id;
```

2. 换行写复合语句中的不同语句。

不推荐：

```ngql
GO FROM "player100" OVER follow REVERSELY YIELD follow._dst AS id | GO FROM $-.id \
OVER serve WHERE $^.player.age > 20 YIELD $^.player.name AS FriendOf, $$.team.name AS Team;
GO FROM "player100" OVER follow REVERSELY YIELD src(edge) AS id | GO FROM $-.id \
OVER serve WHERE properties($^).age > 20 YIELD properties($^).name AS FriendOf, properties($$).name AS Team;
```

推荐：

```ngql
GO FROM "player100" \
OVER follow REVERSELY \
YIELD follow._dst AS id | \
YIELD src(edge) AS id | \
GO FROM $-.id OVER serve \
WHERE $^.player.age > 20 \
YIELD $^.player.name AS FriendOf, $$.team.name AS Team;
WHERE properties($^).age > 20 \
YIELD properties($^).name AS FriendOf, properties($$).name AS Team;
```

3. 子句长度超过80个字符时，在合适的位置换行。
Expand Down Expand Up @@ -218,21 +218,21 @@ nGQL没有严格的构建格式要求，但根据恰当而统一的风格创建n
```ngql
GO FROM "player100" \
OVER follow \
YIELD follow._dst AS id; | \
YIELD dst(edge) AS id; | \
GO FROM $-.id \
OVER serve \
YIELD $$.team.name AS Team, $^.player.name AS Player;
YIELD properties($$).name AS Team, properties($^).name AS Player;
```

支持：

```ngql
GO FROM "player100" \
OVER follow \
YIELD follow._dst AS id | \
YIELD dst(edge) AS id | \
GO FROM $-.id \
OVER serve \
YIELD $$.team.name AS Team, $^.player.name AS Player;
YIELD properties($$).name AS Team, properties($^).name AS Player;
```

3. 在包含自定义变量的复合语句中，用英文分号结束定义变量的语句。不按规则加分号或使用管道符结束该语句会导致执行失败。
Expand All @@ -242,30 +242,30 @@ nGQL没有严格的构建格式要求，但根据恰当而统一的风格创建n
```ngql
$var = GO FROM "player100" \
OVER follow \
YIELD follow._dst AS id \
YIELD dst(edge) AS id \
GO FROM $var.id \
OVER serve \
YIELD $$.team.name AS Team, $^.player.name AS Player;
YIELD properties($$).name AS Team, properties($^).name AS Player;
```

也不支持：

```ngql
$var = GO FROM "player100" \
OVER follow \
YIELD follow._dst AS id | \
YIELD dst(edge) AS id | \
GO FROM $var.id \
OVER serve \
YIELD $$.team.name AS Team, $^.player.name AS Player;
YIELD properties($$).name AS Team, properties($^).name AS Player;
```

支持：

```ngql
$var = GO FROM "player100" \
OVER follow \
YIELD follow._dst AS id; \
YIELD dst(edge) AS id; \
GO FROM $var.id \
OVER serve \
YIELD $$.team.name AS Team, $^.player.name AS Player;
YIELD properties($$).name AS Team, properties($^).name AS Player;
```
2 changes: 1 addition & 1 deletion docs-2.0/3.ngql-guide/12.vertex-statements/4.delete-vertex.md
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Expand Up @@ -24,7 +24,7 @@ nebula> DELETE VERTEX "team1";

```ngql
# 结合管道符，删除符合条件的点。
nebula> GO FROM "player100" OVER serve WHERE serve.start_year == "2021" YIELD serve._dst AS id | DELETE VERTEX $-.id;
nebula> GO FROM "player100" OVER serve WHERE properties(edge).start_year == "2021" YIELD dst(edge) AS id | DELETE VERTEX $-.id;
```

## 删除过程与删除邻边
Expand Down
2 changes: 1 addition & 1 deletion docs-2.0/3.ngql-guide/13.edge-statements/2.update-edge.md
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Expand Up @@ -30,7 +30,7 @@ SET <update_prop>
// 用GO语句查看边的属性值。
nebula> GO FROM "player100" \
OVER serve \
YIELD serve.start_year, serve.end_year;
YIELD properties(edge).start_year, properties(edge).end_year;
+------------------+----------------+
| serve.start_year | serve.end_year |
+------------------+----------------+
Expand Down
2 changes: 1 addition & 1 deletion docs-2.0/3.ngql-guide/13.edge-statements/3.upsert-edge.md
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Expand Up @@ -57,7 +57,7 @@ SET <update_prop>
// 查看如下三个点是否有serve类型的出边，结果“Empty set”表示没有serve类型的出边。
nebula> GO FROM "player666", "player667", "player668" \
OVER serve \
YIELD serve.start_year, serve.end_year;
YIELD properties(edge).start_year, properties(edge).end_year;
Empty set

nebula> UPSERT EDGE on serve \
Expand Down
4 changes: 2 additions & 2 deletions docs-2.0/3.ngql-guide/13.edge-statements/4.delete-edge.md
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Expand Up @@ -22,7 +22,7 @@ nebula> DELETE EDGE serve "player100" -> "team204"@0;
```ngql
# 结合管道符，删除符合条件的边。
nebula> GO FROM "player100" OVER follow \
WHERE follow._dst == "team204" \
YIELD follow._src AS src, follow._dst AS dst, follow._rank AS rank \
WHERE dst(edge) == "team204" \
YIELD src(edge) AS src, dst(edge) AS dst, rank(edge) AS rank \
| DELETE EDGE follow $-.src->$-.dst @ $-.rank;
```
4 changes: 2 additions & 2 deletions docs-2.0/3.ngql-guide/3.data-types/6.list.md
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Expand Up @@ -180,8 +180,8 @@ nebula> RETURN size([1,2,3]);
+---------------+

# 将列表[92,90]中的元素做运算，然后在where子句中进行条件判断。
nebula> GO FROM "player100" OVER follow WHERE follow.degree NOT IN [x IN [92, 90] | x + $$.player.age] \
YIELD follow._dst AS id, follow.degree AS degree;
nebula> GO FROM "player100" OVER follow WHERE properties(edge).degree NOT IN [x IN [92, 90] | x + $$.player.age] \
YIELD dst(edge) AS id, properties(edge).degree AS degree;
+-------------+--------+
| id | degree |
+-------------+--------+
Expand Down
20 changes: 12 additions & 8 deletions docs-2.0/3.ngql-guide/4.variable-and-composite-queries/1.composite-queries.md
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Expand Up @@ -59,12 +59,16 @@ Nebula Graph支持三种方式进行复合查询（或子查询）：

```ngql
# 管道符连接多个查询。
nebula> GO FROM "player100" OVER follow YIELD follow._dst AS id | \
GO FROM $-.id OVER serve YIELD $$.team.name AS Team, \
$^.player.name AS Player;
+---------+-------------+
| Team | Player |
+---------+-------------+
| Nuggets | Tony Parker |
+---------+-------------+
nebula> GO FROM "player100" OVER follow YIELD dst(edge) AS id | \
GO FROM $-.id OVER serve YIELD properties($$).name AS Team, \
properties($^).name AS Player;
+-----------+-----------------+
| Team | Player |
+-----------+-----------------+
| "Spurs" | "Tony Parker" |
+-----------+-----------------+
| "Hornets" | "Tony Parker" |
+-----------+-----------------+
| "Spurs" | "Manu Ginobili" |
+-----------+-----------------+
```
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