This is an automated email from the ASF dual-hosted git repository.
diwu pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/doris.git
The following commit(s) were added to refs/heads/master by this push:
new f3a83cf6db7 [typo](doc)add user-defined variables docs (#26959)
f3a83cf6db7 is described below
commit f3a83cf6db7ff5e98356a51e63eeb42196752bae
Author: ZhenchaoXu <[email protected]>
AuthorDate: Thu Mar 7 16:15:33 2024 +0800
[typo](doc)add user-defined variables docs (#26959)
---
docs/en/docs/advanced/user-defined-variables.md | 115 +++++++++++++++++++++
docs/sidebars.json | 1 +
docs/zh-CN/docs/advanced/user-defined-variables.md | 108 +++++++++++++++++++
3 files changed, 224 insertions(+)
diff --git a/docs/en/docs/advanced/user-defined-variables.md
b/docs/en/docs/advanced/user-defined-variables.md
new file mode 100644
index 00000000000..a11ebc602e9
--- /dev/null
+++ b/docs/en/docs/advanced/user-defined-variables.md
@@ -0,0 +1,115 @@
+---
+{
+ "title": "User Defined Variables",
+ "language": "en"
+}
+---
+
+<!--
+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.
+-->
+
+
+User-defined variables refer to values that users can store in custom
variables using SQL statements, and these variables can be referenced by other
SQL statements. This approach facilitates value passing and simplifies SQL
writing.
+
+## Usage
+
+User-defined variable takes the form: @var_name, where the variable name
consists of letters, numbers, ".", "_", "¥", and "$". However, when referenced
as a string or identifier, it can also include other characters (e.g.
@\`var-name\`), excluding pure numbers and the standalone ".".
+
+## Grammer
+
+User-defined variables can be defined using the SET statement:
+
+```sql
+SET @var_name = expr [, @var_name = expr ...];
+```
+
+Or, using `:=` as the assignment operator:
+
+```sql
+SET @var_name := expr [, @var_name = expr ...];
+```
+
+- When declaring a user-defined variable, the @ prefix is mandatory.
+- Multiple user-defined variables can be declared simultaneously, separated by
commas (,).
+- Multiple declarations of the same variable are allowed, and the newly
declared value will override the original value.
+- The `expr` currently does not support expressions.
+- If an undeclared variable is referenced in a SQL statement, its value
defaults to NULL, and its type is STRING.
+
+User-defined variables can be queried using the SELECT statement:
+
+```sql
+SELECT @var_name [, @var_name ...];
+```
+
+## Use restrictions
+
+- Viewing existing user-defined variables is not currently supported.
+- Assigning a variable to another variable is not currently supported.
+- Declaring BITMAP, HLL, PERCENTILE, and ARRAY type variables is not currently
supported. JSON type variables are converted to STRING for storage.
+- User-defined variables are session-level variables, and all session
variables are released when the client disconnects.
+
+## Example
+
+```sql
+mysql> SET @v1=1, @v2:=2;
+Query OK, 0 rows affected (0.00 sec)
+
+mysql> SELECT @v1,@v2;
++------+------+
+| @v1 | @v2 |
++------+------+
+| 1 | 2 |
++------+------+
+1 row in set (0.00 sec)
+
+mysql> SELECT @v1+@v2;
++-------------+
+| (@v1 + @v2) |
++-------------+
+| 3 |
++-------------+
+1 row in set (0.01 sec)
+
+mysql> SET @`var-name`=2;
+Query OK, 0 rows affected (0.00 sec)
+
+mysql> SELECT @`var-name`;
++-----------+
+| @var-name |
++-----------+
+| 2 |
++-----------+
+1 row in set (0.00 sec)
+
+mysql> SET @j := '{"a": 1, "b": 2, "c": {"d": 4}}';
+Query OK, 0 rows affected (0.00 sec)
+
+mysql> SELECT @j;
++---------------------------------+
+| @j |
++---------------------------------+
+| {"a": 1, "b": 2, "c": {"d": 4}} |
++---------------------------------+
+1 row in set (0.00 sec)
+
+```
+
+
+
+
diff --git a/docs/sidebars.json b/docs/sidebars.json
index eee48955dfa..a6dabe8c859 100644
--- a/docs/sidebars.json
+++ b/docs/sidebars.json
@@ -192,6 +192,7 @@
"advanced/cold-hot-separation",
"advanced/is-being-synced",
"advanced/lateral-view",
+ "advanced/user-defined-variables",
"advanced/auto-increment",
"advanced/is-being-synced"
]
diff --git a/docs/zh-CN/docs/advanced/user-defined-variables.md
b/docs/zh-CN/docs/advanced/user-defined-variables.md
new file mode 100644
index 00000000000..fb62b86f0f6
--- /dev/null
+++ b/docs/zh-CN/docs/advanced/user-defined-variables.md
@@ -0,0 +1,108 @@
+---
+{
+ "title": "用户自定义变量",
+ "language": "zh-CN"
+}
+---
+
+<!--
+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.
+-->
+
+
+自定义变量指的是用户可以根据自身需求通过SQL语句将值存储在自定义的变量中，然后该变量可以被其他SQL语句引用。通过这种方式既可以实现值的传递，又可以简化SQL的编写。
+
+## 使用指南
+用户自定义的变量形式为：@var_name，其中变量名称由字母、数字、“.”、“_”、“¥”、“$”组成。不过，在以字符串或者标识符引用时也可以包含其他字符（例如：@\`var-name`），不支持纯数字和单独“.”的变量。
+
+## 语法
+用户自定义变量可以通过set语句定义
+
+```sql
+SET @var_name = expr [, @var_name = expr ...];
+```
+
+也可以使用:= 用作赋值运算符
+
+```sql
+SET @var_name := expr [, @var_name = expr ...];
+```
+
+- 声明自定义变量时，必须加前缀 @;
+- 可同时声明多个自定义变量，多个变量之间用逗号 (,) 隔开;
+- 支持多次声明同一自定义变量，新声明的值会覆盖原有值;
+- expr暂不支持表达式;
+- 如在一个 SQL 语句中引用了没有声明过的变量，该变量值默认为 NULL 且为 STRING 类型；
+
+读取用户自定义变量可以通过select语句查询
+
+```sql
+SELECT @var_name [, @var_name ...];
+```
+
+## 使用限制
+- 暂不支持查看用户已有的自定义变量；
+- 暂不支持通过变量给变量赋值；
+- 暂不支持声明 BITMAP、HLL、PERCENTILE 和 ARRAY 类型的自定义变量，JSON 类型的自定义变量会转换为 STRING
类型进行存储；
+- 用户自定义变量属于会话级别的变量，当客户端断开时，其所有的会话变量会被释放；
+
+## 示例
+
+```sql
+mysql> SET @v1=1, @v2:=2;
+Query OK, 0 rows affected (0.00 sec)
+
+mysql> select @v1,@v2;
++------+------+
+| @v1 | @v2 |
++------+------+
+| 1 | 2 |
++------+------+
+1 row in set (0.00 sec)
+
+mysql> select @v1+@v2;
++-------------+
+| (@v1 + @v2) |
++-------------+
+| 3 |
++-------------+
+1 row in set (0.01 sec)
+
+mysql> set @`var-name`=2;
+Query OK, 0 rows affected (0.00 sec)
+
+mysql> select @`var-name`;
++-----------+
+| @var-name |
++-----------+
+| 2 |
++-----------+
+1 row in set (0.00 sec)
+
+mysql> SET @j := '{"a": 1, "b": 2, "c": {"d": 4}}';
+Query OK, 0 rows affected (0.00 sec)
+
+mysql> select @j;
++---------------------------------+
+| @j |
++---------------------------------+
+| {"a": 1, "b": 2, "c": {"d": 4}} |
++---------------------------------+
+1 row in set (0.00 sec)
+```
+
\ No newline at end of file
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
