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TDengine
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TDengine
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体验新版 GitCode,发现更多精彩内容 >>
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4299403e
编写于
1月 28, 2021
作者:
E
Elias Soong
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差异文件
[TD-2571] <docs>: add new keyword DISTINCT to select different values of tag column in super table.
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documentation20/webdocs/markdowndocs/TAOS SQL-ch.md
documentation20/webdocs/markdowndocs/TAOS SQL-ch.md
+11
-0
documentation20/webdocs/markdowndocs/administrator-ch.md
documentation20/webdocs/markdowndocs/administrator-ch.md
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documentation20/webdocs/markdowndocs/TAOS SQL-ch.md
浏览文件 @
4299403e
...
...
@@ -470,6 +470,17 @@ Query OK, 2 row(s) in set (0.003112s)
注意:普通表的通配符 * 中并不包含 _标签列_。
##### 获取标签列的去重取值
从 2.0.15 版本开始,支持在超级表查询标签列时,指定 distinct 关键字,这样将返回指定标签列的所有不重复取值。
```
mysql
SELECT DISTINCT tag_name FROM stb_name;
```
注意:目前 distinct 关键字只支持对超级表的标签列进行去重,而不能用于普通列。
#### 结果集列名
```
SELECT
```子句中,如果不指定返回结果集合的列名,结果集列名称默认使用```
SELECT
```子句中的表达式名称作为列名称。此外,用户可使用```
AS
```来重命名返回结果集合中列的名称。例如:
...
...
documentation20/webdocs/markdowndocs/administrator-ch.md
浏览文件 @
4299403e
...
...
@@ -452,39 +452,39 @@ 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 | CONNECTION | G
T | MNODES | SLIDING
|
| ABORT | CONNECTIONS |
ID | MODULES | SMALLINT
|
| ACCOUNT | COPY | I
F | NCHAR | SPREAD
|
| ACCOUNTS | COUNT | I
GNORE | NE | STABLE
|
| ADD | CREATE | I
MMEDIATE | NONE | STABLES
|
| AFTER | CTIME | IM
PORT | NOT | STAR
|
| ALL | DATABASE | I
N | NOTNULL | STATEMENT
|
| ALTER | DATABASES | IN
ITIALLY | NOW | STDDEV
|
| AND | DAYS | IN
SERT | OF | STREAM
|
| AS | DEFERRED | INS
TEAD | OFFSET | STREAMS
|
| ASC | DELIMITERS | IN
TEGER | OR | STRING
|
| ATTACH | DESC | INTE
RVAL | ORDER | SUM
|
| AVG | DESCRIBE | INT
O | PASS | TABLE
|
| BEFORE | DETACH | I
P | PERCENTILE | TABLES
|
| BEGIN | DIFF | I
S | PLUS | TAG
|
| BETWEEN | DI
VIDE | ISNULL | PRAGMA | TAGS
|
| BIGINT | D
NODE | JOIN | PREV | TBLOCKS
|
| BINARY | DNODE
S | KEEP | PRIVILEGE | TBNAME
|
| BITAND | D
OT | KEY | QUERIES | TIMES
|
| BITNOT | DO
UBLE | KILL | QUERY | TIMESTAMP
|
| BITOR | D
ROP | LAST | RAISE | TINYINT
|
| BOOL |
EACH | LE | REM | TOP
|
| BOTTOM | E
ND | LEASTSQUARES | REPLACE | TRIGGER
|
| BY | E
Q | LIKE | REPLICA | UMINUS
|
| CACHE | E
XISTS | LIMIT | RESET | UPLUS
|
| CASCADE | EX
PLAIN | LINEAR | RESTRICT | USE
|
| CHANGE |
FAIL | LOCAL | ROW | USER
|
| CLOG | F
ILL | LP | ROWS | USERS
|
| CLUSTER | FI
RST | LSHIFT | RP | USING
|
| COLON | F
LOAT | LT | RSHIFT | VALUES
|
| COLUMN | F
OR | MATCH | SCORES | VARIABLE
|
| COMMA | F
ROM | MAX | SELECT | VGROUPS
|
| COMP |
GE | METRIC | SEMI | VIEW
|
| CONCAT | G
LOB | METRICS | SET | WAVG
|
| CONFIGS | G
RANTS | MIN | SHOW | WHERE
|
| CONFLICT | GR
OUP | MINUS | SLASH |
|
| ABLOCKS | CONNECTION | G
ROUP | MINUS | SLASH
|
| ABORT | CONNECTIONS |
GT | MNODES | SLIDING
|
| ACCOUNT | COPY | I
D | MODULES | SMALLINT
|
| ACCOUNTS | COUNT | I
F | NCHAR | SPREAD
|
| ADD | CREATE | I
GNORE | NE | STABLE
|
| AFTER | CTIME | IM
MEDIATE | NONE | STABLES
|
| ALL | DATABASE | I
MPORT | NOT | STAR
|
| ALTER | DATABASES | IN
| NOTNULL | STATEMENT
|
| AND | DAYS | IN
ITIALLY | NOW | STDDEV
|
| AS | DEFERRED | INS
ERT | OF | STREAM
|
| ASC | DELIMITERS | IN
STEAD | OFFSET | STREAMS
|
| ATTACH | DESC | INTE
GER | OR | STRING
|
| AVG | DESCRIBE | INT
ERVAL | ORDER | SUM
|
| BEFORE | DETACH | I
NTO | PASS | TABLE
|
| BEGIN | DIFF | I
P | PERCENTILE | TABLES
|
| BETWEEN | DI
STINCT | IS | PLUS | TAG
|
| BIGINT | D
IVIDE | ISNULL | PRAGMA | TAGS
|
| BINARY | DNODE
| JOIN | PREV | TBLOCKS
|
| BITAND | D
NODES | KEEP | PRIVILEGE | TBNAME
|
| BITNOT | DO
T | KEY | QUERIES | TIMES
|
| BITOR | D
OUBLE | KILL | QUERY | TIMESTAMP
|
| BOOL |
DROP | LAST | RAISE | TINYINT
|
| BOTTOM | E
ACH | LE | REM | TOP
|
| BY | E
ND | LEASTSQUARES | REPLACE | TRIGGER
|
| CACHE | E
Q | LIKE | REPLICA | UMINUS
|
| CASCADE | EX
ISTS | LIMIT | RESET | UPLUS
|
| CHANGE |
EXPLAIN | LINEAR | RESTRICT | USE
|
| CLOG | F
AIL | LOCAL | ROW | USER
|
| CLUSTER | FI
LL | LP | ROWS | USERS
|
| COLON | F
IRST | LSHIFT | RP | USING
|
| COLUMN | F
LOAT | LT | RSHIFT | VALUES
|
| COMMA | F
OR | MATCH | SCORES | VARIABLE
|
| COMP |
FROM | MAX | SELECT | VGROUPS
|
| CONCAT | G
E | METRIC | SEMI | VIEW
|
| CONFIGS | G
LOB | METRICS | SET | WAVG
|
| CONFLICT | GR
ANTS | MIN | SHOW | WHERE
|
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