diff --git a/documentation20/webdocs/markdowndocs/TAOS SQL-ch.md b/documentation20/webdocs/markdowndocs/TAOS SQL-ch.md index 7428b3f41db231fff70eea1f7f043ebfe95a733c..0da28836056ee8e3b50bbf96499a6a3de1d205a4 100644 --- a/documentation20/webdocs/markdowndocs/TAOS SQL-ch.md +++ b/documentation20/webdocs/markdowndocs/TAOS SQL-ch.md @@ -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： diff --git a/documentation20/webdocs/markdowndocs/administrator-ch.md b/documentation20/webdocs/markdowndocs/administrator-ch.md index 160bab4d086b4934478f55a3efa1b1136a8dd053..7c8344d9ca5cb2c9738c9b308406a6c96f871db1 100644 --- a/documentation20/webdocs/markdowndocs/administrator-ch.md +++ b/documentation20/webdocs/markdowndocs/administrator-ch.md @@ -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 | GT | MNODES | SLIDING | -| ABORT | CONNECTIONS | ID | MODULES | SMALLINT | -| ACCOUNT | COPY | IF | NCHAR | SPREAD | -| ACCOUNTS | COUNT | IGNORE | NE | STABLE | -| ADD | CREATE | IMMEDIATE | NONE | STABLES | -| AFTER | CTIME | IMPORT | NOT | STAR | -| ALL | DATABASE | IN | NOTNULL | STATEMENT | -| ALTER | DATABASES | INITIALLY | NOW | STDDEV | -| AND | DAYS | INSERT | OF | STREAM | -| AS | DEFERRED | INSTEAD | OFFSET | STREAMS | -| ASC | DELIMITERS | INTEGER | OR | STRING | -| ATTACH | DESC | INTERVAL | ORDER | SUM | -| AVG | DESCRIBE | INTO | PASS | TABLE | -| BEFORE | DETACH | IP | PERCENTILE | TABLES | -| BEGIN | DIFF | IS | PLUS | TAG | -| BETWEEN | DIVIDE | ISNULL | PRAGMA | TAGS | -| BIGINT | DNODE | JOIN | PREV | TBLOCKS | -| BINARY | DNODES | KEEP | PRIVILEGE | TBNAME | -| BITAND | DOT | KEY | QUERIES | TIMES | -| BITNOT | DOUBLE | KILL | QUERY | TIMESTAMP | -| BITOR | DROP | LAST | RAISE | TINYINT | -| BOOL | EACH | LE | REM | TOP | -| BOTTOM | END | LEASTSQUARES | REPLACE | TRIGGER | -| BY | EQ | LIKE | REPLICA | UMINUS | -| CACHE | EXISTS | LIMIT | RESET | UPLUS | -| CASCADE | EXPLAIN | LINEAR | RESTRICT | USE | -| CHANGE | FAIL | LOCAL | ROW | USER | -| CLOG | FILL | LP | ROWS | USERS | -| CLUSTER | FIRST | LSHIFT | RP | USING | -| COLON | FLOAT | LT | RSHIFT | VALUES | -| COLUMN | FOR | MATCH | SCORES | VARIABLE | -| COMMA | FROM | MAX | SELECT | VGROUPS | -| COMP | GE | METRIC | SEMI | VIEW | -| CONCAT | GLOB | METRICS | SET | WAVG | -| CONFIGS | GRANTS | MIN | SHOW | WHERE | -| CONFLICT | GROUP | MINUS | SLASH | | +| ABLOCKS | CONNECTION | GROUP | MINUS | SLASH | +| ABORT | CONNECTIONS | GT | MNODES | SLIDING | +| ACCOUNT | COPY | ID | MODULES | SMALLINT | +| ACCOUNTS | COUNT | IF | NCHAR | SPREAD | +| ADD | CREATE | IGNORE | NE | STABLE | +| AFTER | CTIME | IMMEDIATE | NONE | STABLES | +| ALL | DATABASE | IMPORT | NOT | STAR | +| ALTER | DATABASES | IN | NOTNULL | STATEMENT | +| AND | DAYS | INITIALLY | NOW | STDDEV | +| AS | DEFERRED | INSERT | OF | STREAM | +| ASC | DELIMITERS | INSTEAD | OFFSET | STREAMS | +| ATTACH | DESC | INTEGER | OR | STRING | +| AVG | DESCRIBE | INTERVAL | ORDER | SUM | +| BEFORE | DETACH | INTO | PASS | TABLE | +| BEGIN | DIFF | IP | PERCENTILE | TABLES | +| BETWEEN | DISTINCT | IS | PLUS | TAG | +| BIGINT | DIVIDE | ISNULL | PRAGMA | TAGS | +| BINARY | DNODE | JOIN | PREV | TBLOCKS | +| BITAND | DNODES | KEEP | PRIVILEGE | TBNAME | +| BITNOT | DOT | KEY | QUERIES | TIMES | +| BITOR | DOUBLE | KILL | QUERY | TIMESTAMP | +| BOOL | DROP | LAST | RAISE | TINYINT | +| BOTTOM | EACH | LE | REM | TOP | +| BY | END | LEASTSQUARES | REPLACE | TRIGGER | +| CACHE | EQ | LIKE | REPLICA | UMINUS | +| CASCADE | EXISTS | LIMIT | RESET | UPLUS | +| CHANGE | EXPLAIN | LINEAR | RESTRICT | USE | +| CLOG | FAIL | LOCAL | ROW | USER | +| CLUSTER | FILL | LP | ROWS | USERS | +| COLON | FIRST | LSHIFT | RP | USING | +| COLUMN | FLOAT | LT | RSHIFT | VALUES | +| COMMA | FOR | MATCH | SCORES | VARIABLE | +| COMP | FROM | MAX | SELECT | VGROUPS | +| CONCAT | GE | METRIC | SEMI | VIEW | +| CONFIGS | GLOB | METRICS | SET | WAVG | +| CONFLICT | GRANTS | MIN | SHOW | WHERE |