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13 changes: 13 additions & 0 deletions src/UserGuide/Master/Tree/Basic-Concept/Query-Data.md
Original file line number Diff line number Diff line change
Expand Up @@ -427,6 +427,19 @@ Total line number = 2
It costs 0.002s
```

**Note:** The requirement to query the latest data point with other filtering conditions can be implemented through function composition. For example:

```
IoTDB> select max_time(*), last_value(*) from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00 and status = false align by device
+-----------------+---------------------+----------------+-----------------------+------------------+
| Device|max_time(temperature)|max_time(status)|last_value(temperature)|last_value(status)|
+-----------------+---------------------+----------------+-----------------------+------------------+
|root.ln.wf01.wt01| 1510077540000| 1510077540000| 21.067368| false|
+-----------------+---------------------+----------------+-----------------------+------------------+
Total line number = 1
It costs 0.021s
```

## 3. `WHERE` CLAUSE

In IoTDB query statements, two filter conditions, **time filter** and **value filter**, are supported.
Expand Down
14 changes: 14 additions & 0 deletions src/UserGuide/V1.3.x/Basic-Concept/Query-Data.md
Original file line number Diff line number Diff line change
Expand Up @@ -427,6 +427,20 @@ Total line number = 2
It costs 0.002s
```

**Note:** The requirement to query the latest data point with other filtering conditions can be implemented through function composition. For example:

```
IoTDB> select max_time(*), last_value(*) from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00 and status = false align by device
+-----------------+---------------------+----------------+-----------------------+------------------+
| Device|max_time(temperature)|max_time(status)|last_value(temperature)|last_value(status)|
+-----------------+---------------------+----------------+-----------------------+------------------+
|root.ln.wf01.wt01| 1510077540000| 1510077540000| 21.067368| false|
+-----------------+---------------------+----------------+-----------------------+------------------+
Total line number = 1
It costs 0.021s
```


## `WHERE` CLAUSE

In IoTDB query statements, two filter conditions, **time filter** and **value filter**, are supported.
Expand Down
14 changes: 14 additions & 0 deletions src/UserGuide/dev-1.3/Basic-Concept/Query-Data.md
Original file line number Diff line number Diff line change
Expand Up @@ -427,6 +427,20 @@ Total line number = 2
It costs 0.002s
```

**Note:** The requirement to query the latest data point with other filtering conditions can be implemented through function composition. For example:

```
IoTDB> select max_time(*), last_value(*) from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00 and status = false align by device
+-----------------+---------------------+----------------+-----------------------+------------------+
| Device|max_time(temperature)|max_time(status)|last_value(temperature)|last_value(status)|
+-----------------+---------------------+----------------+-----------------------+------------------+
|root.ln.wf01.wt01| 1510077540000| 1510077540000| 21.067368| false|
+-----------------+---------------------+----------------+-----------------------+------------------+
Total line number = 1
It costs 0.021s
```


## `WHERE` CLAUSE

In IoTDB query statements, two filter conditions, **time filter** and **value filter**, are supported.
Expand Down
14 changes: 14 additions & 0 deletions src/UserGuide/latest/Basic-Concept/Query-Data.md
Original file line number Diff line number Diff line change
Expand Up @@ -427,6 +427,20 @@ Total line number = 2
It costs 0.002s
```

**Note:** The requirement to query the latest data point with other filtering conditions can be implemented through function composition. For example:

```
IoTDB> select max_time(*), last_value(*) from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00 and status = false align by device
+-----------------+---------------------+----------------+-----------------------+------------------+
| Device|max_time(temperature)|max_time(status)|last_value(temperature)|last_value(status)|
+-----------------+---------------------+----------------+-----------------------+------------------+
|root.ln.wf01.wt01| 1510077540000| 1510077540000| 21.067368| false|
+-----------------+---------------------+----------------+-----------------------+------------------+
Total line number = 1
It costs 0.021s
```


## 3. `WHERE` CLAUSE

In IoTDB query statements, two filter conditions, **time filter** and **value filter**, are supported.
Expand Down
14 changes: 14 additions & 0 deletions src/zh/UserGuide/Master/Tree/Basic-Concept/Query-Data.md
Original file line number Diff line number Diff line change
Expand Up @@ -680,6 +680,20 @@ Total line number = 2
It costs 0.002s
```

**注意:** 可以通过函数组合方式实现其他过滤条件查询最新点的需求,例如

```
IoTDB> select max_time(*), last_value(*) from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00 and status = false align by device
+-----------------+---------------------+----------------+-----------------------+------------------+
| Device|max_time(temperature)|max_time(status)|last_value(temperature)|last_value(status)|
+-----------------+---------------------+----------------+-----------------------+------------------+
|root.ln.wf01.wt01| 1510077540000| 1510077540000| 21.067368| false|
+-----------------+---------------------+----------------+-----------------------+------------------+
Total line number = 1
It costs 0.021s
```


## 3. 查询过滤条件(WHERE 子句)

`WHERE` 子句指定了对数据行的筛选条件,由一个 `whereCondition` 组成。
Expand Down
14 changes: 14 additions & 0 deletions src/zh/UserGuide/V1.3.x/Basic-Concept/Query-Data.md
Original file line number Diff line number Diff line change
Expand Up @@ -680,6 +680,20 @@ Total line number = 2
It costs 0.002s
```

**注意:** 可以通过函数组合方式实现其他过滤条件查询最新点的需求,例如

```
IoTDB> select max_time(*), last_value(*) from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00 and status = false align by device
+-----------------+---------------------+----------------+-----------------------+------------------+
| Device|max_time(temperature)|max_time(status)|last_value(temperature)|last_value(status)|
+-----------------+---------------------+----------------+-----------------------+------------------+
|root.ln.wf01.wt01| 1510077540000| 1510077540000| 21.067368| false|
+-----------------+---------------------+----------------+-----------------------+------------------+
Total line number = 1
It costs 0.021s
```


## 查询过滤条件(WHERE 子句)

`WHERE` 子句指定了对数据行的筛选条件,由一个 `whereCondition` 组成。
Expand Down
16 changes: 15 additions & 1 deletion src/zh/UserGuide/dev-1.3/Basic-Concept/Query-Data.md
Original file line number Diff line number Diff line change
Expand Up @@ -613,7 +613,7 @@ select last <Path> [COMMA <Path>]* from < PrefixPath > [COMMA < PrefixPath >]* <

其含义是: 查询时间序列 prefixPath.path 中最近时间戳的数据。

- `whereClause` 中当前只支持时间过滤条件,任何其他过滤条件都将会返回异常。当缓存的最新点不满足过滤条件时,IoTDB 需要从存储中获取结果,此时性能将会有所下降。
- `whereClause` 中当前**只支持时间过滤条件**,任何其他过滤条件都将会返回异常。当缓存的最新点不满足过滤条件时,IoTDB 需要从存储中获取结果,此时性能将会有所下降。

- 结果集为四列的结构:

Expand Down Expand Up @@ -680,6 +680,20 @@ Total line number = 2
It costs 0.002s
```

**注意:** 可以通过函数组合方式实现其他过滤条件查询最新点的需求,例如

```
IoTDB> select max_time(*), last_value(*) from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00 and status = false align by device
+-----------------+---------------------+----------------+-----------------------+------------------+
| Device|max_time(temperature)|max_time(status)|last_value(temperature)|last_value(status)|
+-----------------+---------------------+----------------+-----------------------+------------------+
|root.ln.wf01.wt01| 1510077540000| 1510077540000| 21.067368| false|
+-----------------+---------------------+----------------+-----------------------+------------------+
Total line number = 1
It costs 0.021s
```


## 查询过滤条件(WHERE 子句)

`WHERE` 子句指定了对数据行的筛选条件,由一个 `whereCondition` 组成。
Expand Down
14 changes: 14 additions & 0 deletions src/zh/UserGuide/latest/Basic-Concept/Query-Data.md
Original file line number Diff line number Diff line change
Expand Up @@ -680,6 +680,20 @@ Total line number = 2
It costs 0.002s
```

**注意:** 可以通过函数组合方式实现其他过滤条件查询最新点的需求,例如

```
IoTDB> select max_time(*), last_value(*) from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00 and status = false align by device
+-----------------+---------------------+----------------+-----------------------+------------------+
| Device|max_time(temperature)|max_time(status)|last_value(temperature)|last_value(status)|
+-----------------+---------------------+----------------+-----------------------+------------------+
|root.ln.wf01.wt01| 1510077540000| 1510077540000| 21.067368| false|
+-----------------+---------------------+----------------+-----------------------+------------------+
Total line number = 1
It costs 0.021s
```


## 3. 查询过滤条件(WHERE 子句)

`WHERE` 子句指定了对数据行的筛选条件,由一个 `whereCondition` 组成。
Expand Down