未验证 提交 cd5767f4 编写于 作者: E Elias Soong 提交者: GitHub

Merge pull request #5989 from taosdata/docs/Update-Latest-Feature

Docs/update latest feature
......@@ -16,7 +16,6 @@ TDengine 的 JDBC 驱动实现尽可能与关系型数据库驱动保持一致
* TDengine 目前不支持针对单条数据记录的删除操作。
* 目前不支持事务操作。
* 目前不支持表间的 union 操作。
* 目前不支持嵌套查询(nested query)。
* 对每个 Connection 的实例,至多只能有一个打开的 ResultSet 实例;如果在 ResultSet 还没关闭的情况下执行了新的查询,taos-jdbcdriver 会自动关闭上一个 ResultSet。
......@@ -447,7 +446,7 @@ Query OK, 1 row(s) in set (0.000141s)
## TAOS-JDBCDriver 版本以及支持的 TDengine 版本和 JDK 版本
## <a class="anchor" id="version"></a>TAOS-JDBCDriver 版本以及支持的 TDengine 版本和 JDK 版本
| taos-jdbcdriver 版本 | TDengine 版本 | JDK 版本 |
| -------------------- | ----------------- | -------- |
......
......@@ -144,7 +144,7 @@ TDengine集群中加入一个新的dnode时,涉及集群相关的一些参数
- numOfMnodes:系统中管理节点个数。默认值:3。
- balance:是否启动负载均衡。0:否,1:是。默认值:1。
- mnodeEqualVnodeNum: 一个mnode等同于vnode消耗的个数。默认值:4。
- offlineThreshold: dnode离线阈值,超过该时间将导致该dnode从集群中删除。单位为秒,默认值:86400*100(即100天)。
- offlineThreshold: dnode离线阈值,超过该时间将导致该dnode从集群中删除。单位为秒,默认值:86400*10(即10天)。
- statusInterval: dnode向mnode报告状态时长。单位为秒,默认值:1。
- maxTablesPerVnode: 每个vnode中能够创建的最大表个数。默认值:1000000。
- maxVgroupsPerDb: 每个数据库中能够使用的最大vgroup个数。
......@@ -462,31 +462,31 @@ TDengine的所有可执行文件默认存放在 _/usr/local/taos/bin_ 目录下
| 关键字列表 | | | | |
| ---------- | ----------- | ------------ | ---------- | --------- |
| ABLOCKS | CONNECTIONS | HAVING | MODULES | SLIMIT |
| ABORT | COPY | ID | NCHAR | SMALLINT |
| ACCOUNT | COUNT | IF | NE | SPREAD |
| ACCOUNTS | CREATE | IGNORE | NONE | STABLE |
| ADD | CTIME | IMMEDIATE | NOT | STABLES |
| AFTER | DATABASE | IMPORT | NOTNULL | STAR |
| ALL | DATABASES | IN | NOW | STATEMENT |
| ALTER | DAYS | INITIALLY | OF | STDDEV |
| AND | DEFERRED | INSERT | OFFSET | STREAM |
| AS | DELIMITERS | INSTEAD | OR | STREAMS |
| ASC | DESC | INTEGER | ORDER | STRING |
| ATTACH | DESCRIBE | INTERVAL | PASS | SUM |
| AVG | DETACH | INTO | PERCENTILE | TABLE |
| BEFORE | DIFF | IP | PLUS | TABLES |
| BEGIN | DISTINCT | IS | PRAGMA | TAG |
| BETWEEN | DIVIDE | ISNULL | PREV | TAGS |
| BIGINT | DNODE | JOIN | PRIVILEGE | TBLOCKS |
| BINARY | DNODES | KEEP | QUERIES | TBNAME |
| BITAND | DOT | KEY | QUERY | TIMES |
| BITNOT | DOUBLE | KILL | RAISE | TIMESTAMP |
| BITOR | DROP | LAST | REM | TINYINT |
| BOOL | EACH | LE | REPLACE | TOP |
| BOTTOM | END | LEASTSQUARES | REPLICA | TOPIC |
| BY | EQ | LIKE | RESET | TRIGGER |
| CACHE | EXISTS | LIMIT | RESTRICT | UMINUS |
| 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 |
......@@ -498,5 +498,5 @@ TDengine的所有可执行文件默认存放在 _/usr/local/taos/bin_ 目录下
| CONCAT | GLOB | METRICS | SHOW | VIEW |
| CONFIGS | GRANTS | MIN | SLASH | WAVG |
| CONFLICT | GROUP | MINUS | SLIDING | WHERE |
| CONNECTION | GT | MNODES | | |
| CONNECTION | GT | MNODES | SLIMIT | |
......@@ -407,7 +407,7 @@ SELECT select_expr [, select_expr ...]
[INTERVAL (interval_val [, interval_offset])]
[SLIDING sliding_val]
[FILL fill_val]
[GROUP BY col_list <!-- [HAVING having_condition] -->]
[GROUP BY col_list]
[ORDER BY col_list { DESC | ASC }]
[SLIMIT limit_val [SOFFSET offset_val]]
[LIMIT limit_val [OFFSET offset_val]]
......@@ -647,7 +647,7 @@ Query OK, 1 row(s) in set (0.001091s)
3. 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”。
<!--
### GROUP BY 之后的 HAVING 过滤
### <a class="anchor" id="having"></a>GROUP BY 之后的 HAVING 过滤
从 2.0.20 版本开始,GROUP BY 之后允许再跟一个 HAVING 子句,对成组后的各组数据再做筛选。HAVING 子句可以使用聚合函数和选择函数作为过滤条件(但暂时不支持 LEASTSQUARES、TOP、BOTTOM、LAST_ROW)。
......@@ -657,6 +657,16 @@ SELECT AVG(f1), SPREAD(f1, f2, st2.f1) FROM st2 WHERE f1 > 0 GROUP BY f1 HAVING
```
-->
### <a class="anchor" id="union"></a>UNION ALL 操作符
```mysql
SELECT ...
UNION ALL SELECT ...
[UNION ALL SELECT ...]
```
TDengine 支持 UNION ALL 操作符。也就是说,如果多个 SELECT 子句返回结果集的结构完全相同(列名、列类型、列数、顺序),那么可以通过 UNION ALL 把这些结果集合并到一起。目前只支持 UNION ALL 模式,也即在结果集的合并过程中是不去重的。
### SQL 示例
- 对于下面的例子,表tb1用以下语句创建
......
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