From b437febaa04e50699caa404463a0131446ce41f6 Mon Sep 17 00:00:00 2001 From: Elias Soong Date: Fri, 30 Apr 2021 17:24:58 +0800 Subject: [PATCH] [TD-3984] : describe "union all" clause. --- .../cn/08.connector/01.java/docs.md | 3 +- documentation20/cn/11.administrator/docs.md | 52 +++++++++---------- documentation20/cn/12.taos-sql/docs.md | 14 ++++- 3 files changed, 39 insertions(+), 30 deletions(-) diff --git a/documentation20/cn/08.connector/01.java/docs.md b/documentation20/cn/08.connector/01.java/docs.md index 3442a2248c..5eec33e2f1 100644 --- a/documentation20/cn/08.connector/01.java/docs.md +++ b/documentation20/cn/08.connector/01.java/docs.md @@ -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 +## 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 | | -------------------- | ----------------- | -------- | diff --git a/documentation20/cn/11.administrator/docs.md b/documentation20/cn/11.administrator/docs.md index f8dc794d7d..bfa0456c7d 100644 --- a/documentation20/cn/11.administrator/docs.md +++ b/documentation20/cn/11.administrator/docs.md @@ -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 | | diff --git a/documentation20/cn/12.taos-sql/docs.md b/documentation20/cn/12.taos-sql/docs.md index 04c90748f2..112ad99391 100644 --- a/documentation20/cn/12.taos-sql/docs.md +++ b/documentation20/cn/12.taos-sql/docs.md @@ -407,7 +407,7 @@ SELECT select_expr [, select_expr ...] [INTERVAL (interval_val [, interval_offset])] [SLIDING sliding_val] [FILL fill_val] - [GROUP BY col_list ] + [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”。 +### 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 -- GitLab