未验证 提交 c9f832f4 编写于 作者: E Elias Soong 提交者: GitHub

Merge pull request #6658 from taosdata/docs/Update-Latest-Feature

Docs/update latest feature
......@@ -466,42 +466,43 @@ TDengine的所有可执行文件默认存放在 _/usr/local/taos/bin_ 目录下
目前 TDengine 有将近 200 个内部保留关键字,这些关键字无论大小写均不可以用作库名、表名、STable 名、数据列名及标签列名等。这些关键字列表如下:
| 关键字列表 | | | | |
| ---------- | ----------- | ------------ | ---------- | --------- |
| ABLOCKS | CONNECTIONS | HAVING | MODULES | SMALLINT |
| ABORT | COPY | ID | NCHAR | SPREAD |
| ACCOUNT | COUNT | IF | NE | STABLE |
| ACCOUNTS | CREATE | IGNORE | NONE | STABLES |
| ADD | CTIME | IMMEDIATE | NOT | STAR |
| AFTER | DATABASE | IMPORT | NOTNULL | STATEMENT |
| ALL | DATABASES | IN | NOW | STDDEV |
| ALTER | DAYS | INITIALLY | OF | STREAM |
| AND | DEFERRED | INSERT | OFFSET | STREAMS |
| AS | DELIMITERS | INSTEAD | OR | STRING |
| ASC | DESC | INTEGER | ORDER | SUM |
| ATTACH | DESCRIBE | INTERVAL | PASS | TABLE |
| AVG | DETACH | INTO | PERCENTILE | TABLES |
| BEFORE | DIFF | IP | PLUS | TAG |
| BEGIN | DISTINCT | IS | PRAGMA | TAGS |
| BETWEEN | DIVIDE | ISNULL | PREV | TBLOCKS |
| BIGINT | DNODE | JOIN | PRIVILEGE | TBNAME |
| BINARY | DNODES | KEEP | QUERIES | TIMES |
| BITAND | DOT | KEY | QUERY | TIMESTAMP |
| BITNOT | DOUBLE | KILL | RAISE | TINYINT |
| BITOR | DROP | LAST | REM | TOP |
| BOOL | EACH | LE | REPLACE | TOPIC |
| BOTTOM | END | LEASTSQUARES | REPLICA | TRIGGER |
| BY | EQ | LIKE | RESET | UMINUS |
| CACHE | EXISTS | LIMIT | RESTRICT | UNION |
| CASCADE | EXPLAIN | LINEAR | ROW | UPLUS |
| CHANGE | FAIL | LOCAL | ROWS | USE |
| CLOG | FILL | LP | RP | USER |
| CLUSTER | FIRST | LSHIFT | RSHIFT | USERS |
| COLON | FLOAT | LT | SCORES | USING |
| COLUMN | FOR | MATCH | SELECT | VALUES |
| COMMA | FROM | MAX | SEMI | VARIABLE |
| COMP | GE | METRIC | SET | VGROUPS |
| CONCAT | GLOB | METRICS | SHOW | VIEW |
| CONFIGS | GRANTS | MIN | SLASH | WAVG |
| CONFLICT | GROUP | MINUS | SLIDING | WHERE |
| CONNECTION | GT | MNODES | SLIMIT | |
| ------------ | ------------ | ------------ | ------------ | ------------ |
| ABORT | CREATE | IGNORE | NULL | STAR |
| ACCOUNT | CTIME | IMMEDIATE | OF | STATE |
| ACCOUNTS | DATABASE | IMPORT | OFFSET | STATEMENT |
| ADD | DATABASES | IN | OR | STATE_WINDOW |
| AFTER | DAYS | INITIALLY | ORDER | STORAGE |
| ALL | DBS | INSERT | PARTITIONS | STREAM |
| ALTER | DEFERRED | INSTEAD | PASS | STREAMS |
| AND | DELIMITERS | INT | PLUS | STRING |
| AS | DESC | INTEGER | PPS | SYNCDB |
| ASC | DESCRIBE | INTERVAL | PRECISION | TABLE |
| ATTACH | DETACH | INTO | PREV | TABLES |
| BEFORE | DISTINCT | IS | PRIVILEGE | TAG |
| BEGIN | DIVIDE | ISNULL | QTIME | TAGS |
| BETWEEN | DNODE | JOIN | QUERIES | TBNAME |
| BIGINT | DNODES | KEEP | QUERY | TIMES |
| BINARY | DOT | KEY | QUORUM | TIMESTAMP |
| BITAND | DOUBLE | KILL | RAISE | TINYINT |
| BITNOT | DROP | LE | REM | TOPIC |
| BITOR | EACH | LIKE | REPLACE | TOPICS |
| BLOCKS | END | LIMIT | REPLICA | TRIGGER |
| BOOL | EQ | LINEAR | RESET | TSERIES |
| BY | EXISTS | LOCAL | RESTRICT | UMINUS |
| CACHE | EXPLAIN | LP | ROW | UNION |
| CACHELAST | FAIL | LSHIFT | RP | UNSIGNED |
| CASCADE | FILE | LT | RSHIFT | UPDATE |
| CHANGE | FILL | MATCH | SCORES | UPLUS |
| CLUSTER | FLOAT | MAXROWS | SELECT | USE |
| COLON | FOR | MINROWS | SEMI | USER |
| COLUMN | FROM | MINUS | SESSION | USERS |
| COMMA | FSYNC | MNODES | SET | USING |
| COMP | GE | MODIFY | SHOW | VALUES |
| COMPACT | GLOB | MODULES | SLASH | VARIABLE |
| CONCAT | GRANTS | NCHAR | SLIDING | VARIABLES |
| CONFLICT | GROUP | NE | SLIMIT | VGROUPS |
| CONNECTION | GT | NONE | SMALLINT | VIEW |
| CONNECTIONS | HAVING | NOT | SOFFSET | VNODES |
| CONNS | ID | NOTNULL | STABLE | WAL |
| COPY | IF | NOW | STABLES | WHERE |
......@@ -89,13 +89,13 @@ TDengine 缺省的时间戳是毫秒精度,但通过在 CREATE DATABASE 时传
```mysql
USE db_name;
```
使用/切换数据库
使用/切换数据库(在 RESTful 连接方式下无效)。
- **删除数据库**
```mysql
DROP DATABASE [IF EXISTS] db_name;
```
删除数据库。所包含的全部数据表将被删除,谨慎使用
删除数据库。指定 Database 所包含的全部数据表将被删除,谨慎使用!
- **修改数据库参数**
```mysql
......@@ -704,7 +704,7 @@ Query OK, 1 row(s) in set (0.001091s)
### 支持的条件过滤操作
| **Operation** | **Note** | **Applicable Data Types** |
| --------------- | ----------------------------- | ------------------------------------- |
| --------------- | ----------------------------- | ----------------------------------------- |
| > | larger than | **`timestamp`** and all numeric types |
| < | smaller than | **`timestamp`** and all numeric types |
| >= | larger than or equal to | **`timestamp`** and all numeric types |
......@@ -712,13 +712,15 @@ Query OK, 1 row(s) in set (0.001091s)
| = | equal to | all types |
| <> | not equal to | all types |
| between and | within a certain range | **`timestamp`** and all numeric types |
| in | matches any value in a set | all types except first column `timestamp` |
| % | match with any char sequences | **`binary`** **`nchar`** |
| _ | match with a single char | **`binary`** **`nchar`** |
1. <> 算子也可以写为 != ,请注意,这个算子不能用于数据表第一列的 timestamp 字段。
2. 同时进行多个字段的范围过滤,需要使用关键词 AND 来连接不同的查询条件,暂不支持 OR 连接的不同列之间的查询过滤条件。
3. 针对单一字段的过滤,如果是时间过滤条件,则一条语句中只支持设定一个;但针对其他的(普通)列或标签列,则可以使用 `OR` 关键字进行组合条件的查询过滤。例如:((value > 20 AND value < 30) OR (value < 12)) 。
4. 从 2.0.17 版本开始,条件过滤开始支持 BETWEEN AND 语法,例如 `WHERE col2 BETWEEN 1.5 AND 3.25` 表示查询条件为“1.5 ≤ col2 ≤ 3.25”。
3. 针对单一字段的过滤,如果是时间过滤条件,则一条语句中只支持设定一个;但针对其他的(普通)列或标签列,则可以使用 `OR` 关键字进行组合条件的查询过滤。例如: `((value > 20 AND value < 30) OR (value < 12))`。
4. 从 2.0.17.0 版本开始,条件过滤开始支持 BETWEEN AND 语法,例如 `WHERE col2 BETWEEN 1.5 AND 3.25` 表示查询条件为“1.5 ≤ col2 ≤ 3.25”。
5. 从 2.1.4.0 版本开始,条件过滤开始支持 IN 算子,例如 `WHERE city IN ('Beijing', 'Shanghai')`。说明:BOOL 类型写作 `{true, false}` 或 `{0, 1}` 均可,但不能写作 0、1 之外的整数;FLOAT 和 DOUBLE 类型会受到浮点数精度影响,集合内的值在精度范围内认为和数据行的值完全相等才能匹配成功。<!-- REPLACE_OPEN_TO_ENTERPRISE__IN_OPERATOR_AND_UNSIGNED_INTEGER -->
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