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new 093dfe3f Add Tableless Query doc for V2.0.11 table model (#1205)
093dfe3f is described below
commit 093dfe3f6fad90be59b6e14e9cb5fad4c54e79ac
Author: leto-bbq <[email protected]>
AuthorDate: Fri Sep 11 17:38:53 2026 +0800
Add Tableless Query doc for V2.0.11 table model (#1205)
---
src/.vuepress/sidebar/V2.0.x/en-Table.ts | 1 +
src/.vuepress/sidebar/V2.0.x/zh-Table.ts | 1 +
.../Table/SQL-Manual/Tableless-Query_apache.md | 131 +++++++++++++++++++++
.../SQL-Manual/Tableless-Query_apache.md | 131 +++++++++++++++++++++
.../Table/SQL-Manual/Tableless-Query_apache.md | 131 +++++++++++++++++++++
.../SQL-Manual/Tableless-Query_apache.md | 131 +++++++++++++++++++++
6 files changed, 526 insertions(+)
diff --git a/src/.vuepress/sidebar/V2.0.x/en-Table.ts
b/src/.vuepress/sidebar/V2.0.x/en-Table.ts
index 22ec220e..65973ed5 100644
--- a/src/.vuepress/sidebar/V2.0.x/en-Table.ts
+++ b/src/.vuepress/sidebar/V2.0.x/en-Table.ts
@@ -235,6 +235,7 @@ export const enSidebar = {
collapsible: true,
children: [
{ text: 'overview', link: 'overview_apache' },
+ { text: 'Tableless Query', link: 'Tableless-Query_apache' },
{ text: 'SELECT Clause', link: 'Select-Clause_apache' },
{ text: 'FROM&JOIN Clause', link: 'From-Join-Clause' },
{ text: 'WHERE Clause', link: 'Where-Clause' },
diff --git a/src/.vuepress/sidebar/V2.0.x/zh-Table.ts
b/src/.vuepress/sidebar/V2.0.x/zh-Table.ts
index 900752c4..0d575a0b 100644
--- a/src/.vuepress/sidebar/V2.0.x/zh-Table.ts
+++ b/src/.vuepress/sidebar/V2.0.x/zh-Table.ts
@@ -235,6 +235,7 @@ export const zhSidebar = {
collapsible: true,
children: [
{ text: '概览', link: 'overview_apache' },
+ { text: '无表查询', link: 'Tableless-Query_apache' },
{ text: 'SELECT子句', link: 'Select-Clause_apache' },
{ text: 'FROM&JOIN子句', link: 'From-Join-Clause' },
{ text: 'WHERE子句', link: 'Where-Clause' },
diff --git a/src/UserGuide/Master/Table/SQL-Manual/Tableless-Query_apache.md
b/src/UserGuide/Master/Table/SQL-Manual/Tableless-Query_apache.md
new file mode 100644
index 00000000..d75d4f2e
--- /dev/null
+++ b/src/UserGuide/Master/Table/SQL-Manual/Tableless-Query_apache.md
@@ -0,0 +1,131 @@
+<!--
+
+ Licensed to the Apache Software Foundation (ASF) under one
+ or more contributor license agreements. See the NOTICE file
+ distributed with this work for additional information
+ regarding copyright ownership. The ASF licenses this file
+ to you under the Apache License, Version 2.0 (the
+ "License"); you may not use this file except in compliance
+ with the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing,
+ software distributed under the License is distributed on an
+ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ KIND, either express or implied. See the License for the
+ specific language governing permissions and limitations
+ under the License.
+
+-->
+
+# Tableless Query
+
+## 1. Overview
+
+Tableless query allows you to execute SQL statements without a `FROM` clause,
without relying on any actual database table. It retrieves computed results,
constant values, or system information, and is mainly used in scenarios such as
expression evaluation, system function calls, and constant queries.
+
+> Note: This feature is supported since V2.0.11.
+
+## 2. Syntax
+
+```sql
+SELECT expression [ [ AS ] column_alias ]
+ [, expression [ [ AS ] column_alias ] ]*;
+```
+
+Where:
+
+- `expression`: the expression to be evaluated. It can be a constant, a
mathematical function, a string function, a date-time function, or an aggregate
function. Currently, only functions that take **no arguments or constant
arguments only** are supported.
+
+- `column_alias`: an optional alias for the result column, which improves the
readability of query results. If no alias is specified, the system
automatically generates column names such as `_col0`, `_col1`, etc.
+
+- `SELECT *` is not supported.
+
+- When executing `SELECT COUNT(*);`, the result is always `1`.
+
+## 3. Examples
+
+### 3.1 Constants and Mathematical Calculations
+
+Query statement:
+
+```sql
+SELECT 100 + 50 AS sum_result,
+ 10 * 5 AS product,
+ SQRT(144) AS square_root,
+ ABS(-25) AS absolute_value,
+ SIN(1) AS sin_value;
+```
+
+Result:
+
+```text
++----------+-------+-----------+--------------+------------------+
+|sum_result|product|square_root|absolute_value| sin_value|
++----------+-------+-----------+--------------+------------------+
+| 150| 50| 12.0| 25|0.8414709848078965|
++----------+-------+-----------+--------------+------------------+
+```
+
+### 3.2 String Functions
+
+Query statement:
+
+```sql
+SELECT
+ CONCAT('Hello', ' ', 'World') AS greeting,
+ UPPER('iotdb') AS uppercase,
+ LOWER('IOTDB') AS lowercase,
+ LENGTH('database') AS str_length;
+```
+
+Result:
+
+```text
++-----------+---------+---------+----------+
+| greeting|uppercase|lowercase|str_length|
++-----------+---------+---------+----------+
+|Hello World| IOTDB| iotdb| 8|
++-----------+---------+---------+----------+
+```
+
+### 3.3 Date and Time Functions
+
+Query statement:
+
+```sql
+SELECT NOW() AS now_time;
+```
+
+Result:
+
+```text
++-------------+
+| now_time|
++-------------+
+|1784776724555|
++-------------+
+```
+
+### 3.4 Aggregate Functions
+
+Query statement:
+
+```sql
+SELECT
+ AVG(10),
+ SUM(10),
+ COUNT(10),
+ COUNT(*);
+```
+
+Result:
+
+```text
++-----+-----+-----+-----+
+|_col0|_col1|_col2|_col3|
++-----+-----+-----+-----+
+| 10.0| 10.0| 1| 1|
++-----+-----+-----+-----+
+```
diff --git a/src/UserGuide/latest-Table/SQL-Manual/Tableless-Query_apache.md
b/src/UserGuide/latest-Table/SQL-Manual/Tableless-Query_apache.md
new file mode 100644
index 00000000..d75d4f2e
--- /dev/null
+++ b/src/UserGuide/latest-Table/SQL-Manual/Tableless-Query_apache.md
@@ -0,0 +1,131 @@
+<!--
+
+ Licensed to the Apache Software Foundation (ASF) under one
+ or more contributor license agreements. See the NOTICE file
+ distributed with this work for additional information
+ regarding copyright ownership. The ASF licenses this file
+ to you under the Apache License, Version 2.0 (the
+ "License"); you may not use this file except in compliance
+ with the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing,
+ software distributed under the License is distributed on an
+ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ KIND, either express or implied. See the License for the
+ specific language governing permissions and limitations
+ under the License.
+
+-->
+
+# Tableless Query
+
+## 1. Overview
+
+Tableless query allows you to execute SQL statements without a `FROM` clause,
without relying on any actual database table. It retrieves computed results,
constant values, or system information, and is mainly used in scenarios such as
expression evaluation, system function calls, and constant queries.
+
+> Note: This feature is supported since V2.0.11.
+
+## 2. Syntax
+
+```sql
+SELECT expression [ [ AS ] column_alias ]
+ [, expression [ [ AS ] column_alias ] ]*;
+```
+
+Where:
+
+- `expression`: the expression to be evaluated. It can be a constant, a
mathematical function, a string function, a date-time function, or an aggregate
function. Currently, only functions that take **no arguments or constant
arguments only** are supported.
+
+- `column_alias`: an optional alias for the result column, which improves the
readability of query results. If no alias is specified, the system
automatically generates column names such as `_col0`, `_col1`, etc.
+
+- `SELECT *` is not supported.
+
+- When executing `SELECT COUNT(*);`, the result is always `1`.
+
+## 3. Examples
+
+### 3.1 Constants and Mathematical Calculations
+
+Query statement:
+
+```sql
+SELECT 100 + 50 AS sum_result,
+ 10 * 5 AS product,
+ SQRT(144) AS square_root,
+ ABS(-25) AS absolute_value,
+ SIN(1) AS sin_value;
+```
+
+Result:
+
+```text
++----------+-------+-----------+--------------+------------------+
+|sum_result|product|square_root|absolute_value| sin_value|
++----------+-------+-----------+--------------+------------------+
+| 150| 50| 12.0| 25|0.8414709848078965|
++----------+-------+-----------+--------------+------------------+
+```
+
+### 3.2 String Functions
+
+Query statement:
+
+```sql
+SELECT
+ CONCAT('Hello', ' ', 'World') AS greeting,
+ UPPER('iotdb') AS uppercase,
+ LOWER('IOTDB') AS lowercase,
+ LENGTH('database') AS str_length;
+```
+
+Result:
+
+```text
++-----------+---------+---------+----------+
+| greeting|uppercase|lowercase|str_length|
++-----------+---------+---------+----------+
+|Hello World| IOTDB| iotdb| 8|
++-----------+---------+---------+----------+
+```
+
+### 3.3 Date and Time Functions
+
+Query statement:
+
+```sql
+SELECT NOW() AS now_time;
+```
+
+Result:
+
+```text
++-------------+
+| now_time|
++-------------+
+|1784776724555|
++-------------+
+```
+
+### 3.4 Aggregate Functions
+
+Query statement:
+
+```sql
+SELECT
+ AVG(10),
+ SUM(10),
+ COUNT(10),
+ COUNT(*);
+```
+
+Result:
+
+```text
++-----+-----+-----+-----+
+|_col0|_col1|_col2|_col3|
++-----+-----+-----+-----+
+| 10.0| 10.0| 1| 1|
++-----+-----+-----+-----+
+```
diff --git a/src/zh/UserGuide/Master/Table/SQL-Manual/Tableless-Query_apache.md
b/src/zh/UserGuide/Master/Table/SQL-Manual/Tableless-Query_apache.md
new file mode 100644
index 00000000..b412fea2
--- /dev/null
+++ b/src/zh/UserGuide/Master/Table/SQL-Manual/Tableless-Query_apache.md
@@ -0,0 +1,131 @@
+<!--
+
+ Licensed to the Apache Software Foundation (ASF) under one
+ or more contributor license agreements. See the NOTICE file
+ distributed with this work for additional information
+ regarding copyright ownership. The ASF licenses this file
+ to you under the Apache License, Version 2.0 (the
+ "License"); you may not use this file except in compliance
+ with the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing,
+ software distributed under the License is distributed on an
+ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ KIND, either express or implied. See the License for the
+ specific language governing permissions and limitations
+ under the License.
+
+-->
+
+# 无表查询
+
+## 1. 功能概述
+
+无表查询支持在不依赖实际数据库表的情况下，直接执行不包含 `FROM` 子句的 SQL
查询语句，获取计算结果、常量值或系统信息，主要用于表达式计算、系统函数调用、常量查询等场景。
+
+> 注意：自 V2.0.11 版本起支持该功能。
+
+## 2. 语法定义
+
+```sql
+SELECT expression [ [ AS ] column_alias ]
+ [, expression [ [ AS ] column_alias ] ]*;
+```
+
+其中：
+
+- `expression`：待计算的表达式，可以是常量、数学函数、字符串函数、日期时间函数、聚合函数，目前支持**无参数或只需传入常量参数**的函数。
+
+- `column_alias`：可选的结果列别名，用于提升查询结果的可读性。未指定别名时，系统会自动生成 `_col0`、`_col1` 等列名。
+
+- 不支持使用 `SELECT *`。
+
+- 执行 `SELECT COUNT(*);` 时，结果始终为 `1`。
+
+## 3. 使用示例
+
+### 3.1 常量与数学计算
+
+查询语句：
+
+```sql
+SELECT 100 + 50 AS sum_result,
+ 10 * 5 AS product,
+ SQRT(144) AS square_root,
+ ABS(-25) AS absolute_value,
+ SIN(1) AS sin_value;
+```
+
+返回结果：
+
+```text
++----------+-------+-----------+--------------+------------------+
+|sum_result|product|square_root|absolute_value| sin_value|
++----------+-------+-----------+--------------+------------------+
+| 150| 50| 12.0| 25|0.8414709848078965|
++----------+-------+-----------+--------------+------------------+
+```
+
+### 3.2 字符串函数
+
+查询语句：
+
+```sql
+SELECT
+ CONCAT('Hello', ' ', 'World') AS greeting,
+ UPPER('iotdb') AS uppercase,
+ LOWER('IOTDB') AS lowercase,
+ LENGTH('database') AS str_length;
+```
+
+返回结果：
+
+```text
++-----------+---------+---------+----------+
+| greeting|uppercase|lowercase|str_length|
++-----------+---------+---------+----------+
+|Hello World| IOTDB| iotdb| 8|
++-----------+---------+---------+----------+
+```
+
+### 3.3 日期时间函数
+
+查询语句：
+
+```sql
+SELECT NOW() AS now_time;
+```
+
+返回结果：
+
+```text
++-------------+
+| now_time|
++-------------+
+|1784776724555|
++-------------+
+```
+
+### 3.4 聚合函数
+
+查询语句：
+
+```sql
+SELECT
+ AVG(10),
+ SUM(10),
+ COUNT(10),
+ COUNT(*);
+```
+
+返回结果：
+
+```text
++-----+-----+-----+-----+
+|_col0|_col1|_col2|_col3|
++-----+-----+-----+-----+
+| 10.0| 10.0| 1| 1|
++-----+-----+-----+-----+
+```
diff --git a/src/zh/UserGuide/latest-Table/SQL-Manual/Tableless-Query_apache.md
b/src/zh/UserGuide/latest-Table/SQL-Manual/Tableless-Query_apache.md
new file mode 100644
index 00000000..b412fea2
--- /dev/null
+++ b/src/zh/UserGuide/latest-Table/SQL-Manual/Tableless-Query_apache.md
@@ -0,0 +1,131 @@
+<!--
+
+ Licensed to the Apache Software Foundation (ASF) under one
+ or more contributor license agreements. See the NOTICE file
+ distributed with this work for additional information
+ regarding copyright ownership. The ASF licenses this file
+ to you under the Apache License, Version 2.0 (the
+ "License"); you may not use this file except in compliance
+ with the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing,
+ software distributed under the License is distributed on an
+ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ KIND, either express or implied. See the License for the
+ specific language governing permissions and limitations
+ under the License.
+
+-->
+
+# 无表查询
+
+## 1. 功能概述
+
+无表查询支持在不依赖实际数据库表的情况下，直接执行不包含 `FROM` 子句的 SQL
查询语句，获取计算结果、常量值或系统信息，主要用于表达式计算、系统函数调用、常量查询等场景。
+
+> 注意：自 V2.0.11 版本起支持该功能。
+
+## 2. 语法定义
+
+```sql
+SELECT expression [ [ AS ] column_alias ]
+ [, expression [ [ AS ] column_alias ] ]*;
+```
+
+其中：
+
+- `expression`：待计算的表达式，可以是常量、数学函数、字符串函数、日期时间函数、聚合函数，目前支持**无参数或只需传入常量参数**的函数。
+
+- `column_alias`：可选的结果列别名，用于提升查询结果的可读性。未指定别名时，系统会自动生成 `_col0`、`_col1` 等列名。
+
+- 不支持使用 `SELECT *`。
+
+- 执行 `SELECT COUNT(*);` 时，结果始终为 `1`。
+
+## 3. 使用示例
+
+### 3.1 常量与数学计算
+
+查询语句：
+
+```sql
+SELECT 100 + 50 AS sum_result,
+ 10 * 5 AS product,
+ SQRT(144) AS square_root,
+ ABS(-25) AS absolute_value,
+ SIN(1) AS sin_value;
+```
+
+返回结果：
+
+```text
++----------+-------+-----------+--------------+------------------+
+|sum_result|product|square_root|absolute_value| sin_value|
++----------+-------+-----------+--------------+------------------+
+| 150| 50| 12.0| 25|0.8414709848078965|
++----------+-------+-----------+--------------+------------------+
+```
+
+### 3.2 字符串函数
+
+查询语句：
+
+```sql
+SELECT
+ CONCAT('Hello', ' ', 'World') AS greeting,
+ UPPER('iotdb') AS uppercase,
+ LOWER('IOTDB') AS lowercase,
+ LENGTH('database') AS str_length;
+```
+
+返回结果：
+
+```text
++-----------+---------+---------+----------+
+| greeting|uppercase|lowercase|str_length|
++-----------+---------+---------+----------+
+|Hello World| IOTDB| iotdb| 8|
++-----------+---------+---------+----------+
+```
+
+### 3.3 日期时间函数
+
+查询语句：
+
+```sql
+SELECT NOW() AS now_time;
+```
+
+返回结果：
+
+```text
++-------------+
+| now_time|
++-------------+
+|1784776724555|
++-------------+
+```
+
+### 3.4 聚合函数
+
+查询语句：
+
+```sql
+SELECT
+ AVG(10),
+ SUM(10),
+ COUNT(10),
+ COUNT(*);
+```
+
+返回结果：
+
+```text
++-----+-----+-----+-----+
+|_col0|_col1|_col2|_col3|
++-----+-----+-----+-----+
+| 10.0| 10.0| 1| 1|
++-----+-----+-----+-----+
+```
