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TDengine
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docs: add info for geometry

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docs/en/12-taos-sql/01-data-type.md
浏览文件 @ 96a9d033
......@@ -42,10 +42,20 @@ In TDengine, the data types below can be used when specifying a column or tag.
| 14 | NCHAR | User Defined | Multi-byte string that can include multi byte characters like Chinese characters. Each character of NCHAR type consumes 4 bytes storage. The string value should be quoted with single quotes. Literal single quote inside the string must be preceded with backslash, like `\'`. The length must be specified when defining a column or tag of NCHAR type, for example nchar(10) means it can store at most 10 characters of nchar type and will consume fixed storage of 40 bytes. An error will be reported if the string value exceeds the length defined. |
| 15 | JSON | | JSON type can only be used on tags. A tag of json type is excluded with any other tags of any other type. |
| 16 | VARCHAR | User-defined | Alias of BINARY |
| 16 | GEOMETRY | User-defined | Geometry |
:::note
- Each row of the table cannot be longer than 48KB (64KB since version 3.0.5.0) (note that each BINARY/NCHAR/GEOMETRY column takes up an additional 2 bytes of storage space).
- Only ASCII visible characters are suggested to be used in a column or tag of BINARY type. Multi-byte characters must be stored in NCHAR type.
- The length of BINARY can be up to 16,374(data column is 65,517 and tag column is 16,382 since version 3.0.5.0) bytes. The string value must be quoted with single quotes. You must specify a length in bytes for a BINARY value, for example binary(20) for up to twenty single-byte characters. If the data exceeds the specified length, an error will occur. The literal single quote inside the string must be preceded with back slash like `\'`
- The maximum length of the GEOMETRY data column is 65,517 bytes, and the maximum length of the tag column is 16,382 bytes. Supports POINT, LINESTRING, and POLYGON subtypes of 2D. The following table describes the length calculation method:
| # | **Syntax** | **MinLen** | **MaxLen** | **Growth of each point** |
|---|--------------------------------------|------------|------------|--------------------------|
| 1 | POINT(1.0 1.0) | 21 | 21 | NA |
| 2 | LINESTRING(1.0 1.0, 2.0 2.0) | 9+2*16 | 9+4094*16 | +16 |
| 3 | POLYGON((1.0 1.0, 2.0 2.0, 1.0 1.0)) | 13+3*16 | 13+4094*16 | +16 |
- Numeric values in SQL statements will be determined as integer or float type according to whether there is decimal point or whether scientific notation is used, so attention must be paid to avoid overflow. For example, 9999999999999999999 will be considered as overflow because it exceeds the upper limit of long integer, but 9999999999999999999.0 will be considered as a legal float number.
:::
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docs/en/12-taos-sql/03-table.md
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......@@ -9,27 +9,27 @@ You create standard tables and subtables with the `CREATE TABLE` statement.
```sql
CREATE TABLE [IF NOT EXISTS] [db_name.]tb_name (create_definition [, create_definition] ...) [table_options]
CREATE TABLE create_subtable_clause
CREATE TABLE [IF NOT EXISTS] [db_name.]tb_name (create_definition [, create_definition] ...)
[TAGS (create_definition [, create_definition] ...)]
[table_options]
create_subtable_clause: {
create_subtable_clause [create_subtable_clause] ...
| [IF NOT EXISTS] [db_name.]tb_name USING [db_name.]stb_name [(tag_name [, tag_name] ...)] TAGS (tag_value [, tag_value] ...)
}
create_definition:
col_name column_definition
column_definition:
type_name [comment 'string_value']
table_options:
table_option ...
table_option: {
COMMENT 'string_value'
| WATERMARK duration[,duration]
......@@ -45,9 +45,9 @@ table_option: {
1. The first column of a table MUST be of type TIMESTAMP. It is automatically set as the primary key.
2. The maximum length of the table name is 192 bytes.
3. The maximum length of each row is 48k(64k since version 3.0.5.0) bytes, please note that the extra 2 bytes used by each BINARY/NCHAR column are also counted.
3. The maximum length of each row is 48k(64k since version 3.0.5.0) bytes, please note that the extra 2 bytes used by each BINARY/NCHAR/GEOMETRY column are also counted.
4. The name of the subtable can only consist of characters from the English alphabet, digits and underscore. Table names can't start with a digit. Table names are case insensitive.
5. The maximum length in bytes must be specified when using BINARY or NCHAR types.
5. The maximum length in bytes must be specified when using BINARY/NCHAR/GEOMETRY types.
6. Escape character "\`" can be used to avoid the conflict between table names and reserved keywords, above rules will be bypassed when using escape character on table names, but the upper limit for the name length is still valid. The table names specified using escape character are case sensitive.
For example \`aBc\` and \`abc\` are different table names but `abc` and `aBc` are same table names because they are both converted to `abc` internally.
Only ASCII visible characters can be used with escape character.
......@@ -58,7 +58,7 @@ table_option: {
3. MAX_DELAY: specifies the maximum latency for pushing computation results. The default value is 15 minutes or the value of the INTERVAL parameter, whichever is smaller. Enter a value between 0 and 15 minutes in milliseconds, seconds, or minutes. You can enter multiple values separated by commas (,). Note: Retain the default value if possible. Configuring a small MAX_DELAY may cause results to be frequently pushed, affecting storage and query performance. This parameter applies only to supertables and takes effect only when the RETENTIONS parameter has been specified for the database.
4. ROLLUP: specifies aggregate functions to roll up. Rolling up a function provides downsampled results based on multiple axes. This parameter applies only to supertables and takes effect only when the RETENTIONS parameter has been specified for the database. You can specify only one function to roll up. The rollup takes effect on all columns except TS. Enter one of the following values: avg, sum, min, max, last, or first.
5. SMA: specifies functions on which to enable small materialized aggregates (SMA). SMA is user-defined precomputation of aggregates based on data blocks. Enter one of the following values: max, min, or sum This parameter can be used with supertables and standard tables.
6. TTL: specifies the time to live (TTL) for the table. If TTL is specified when creatinga table, after the time period for which the table has been existing is over TTL, TDengine will automatically delete the table. Please be noted that the system may not delete the table at the exact moment that the TTL expires but guarantee there is such a system and finally the table will be deleted. The unit of TTL is in days. The default value is 0, i.e. never expire.
6. TTL: specifies the time to live (TTL) for the table. If TTL is specified when creatinga table, after the time period for which the table has been existing is over TTL, TDengine will automatically delete the table. Please be noted that the system may not delete the table at the exact moment that the TTL expires but guarantee there is such a system and finally the table will be deleted. The unit of TTL is in days. The default value is 0, i.e. never expire.
## Create Subtables
......@@ -88,7 +88,7 @@ You can create multiple subtables in a single SQL statement provided that all su
```sql
ALTER TABLE [db_name.]tb_name alter_table_clause
alter_table_clause: {
alter_table_options
| ADD COLUMN col_name column_type
......@@ -96,10 +96,10 @@ alter_table_clause: {
| MODIFY COLUMN col_name column_type
| RENAME COLUMN old_col_name new_col_name
}
alter_table_options:
alter_table_option ...
alter_table_option: {
TTL value
| COMMENT 'string_value'
......@@ -142,15 +142,15 @@ ALTER TABLE tb_name RENAME COLUMN old_col_name new_col_name
```sql
ALTER TABLE [db_name.]tb_name alter_table_clause
alter_table_clause: {
alter_table_options
| SET TAG tag_name = new_tag_value
}
alter_table_options:
alter_table_option ...
alter_table_option: {
TTL value
| COMMENT 'string_value'
......
docs/en/12-taos-sql/16-operators.md
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......@@ -39,7 +39,7 @@ TDengine supports the `UNION` and `UNION ALL` operations. UNION ALL collects all
| 3 | \>, < | All types except BLOB, MEDIUMBLOB, and JSON | Greater than and less than |
| 4 | \>=, <= | All types except BLOB, MEDIUMBLOB, and JSON | Greater than or equal to and less than or equal to |
| 5 | IS [NOT] NULL | All types | Indicates whether the value is null |
| 6 | [NOT] BETWEEN AND | All types except BLOB, MEDIUMBLOB, and JSON | Closed interval comparison |
| 6 | [NOT] BETWEEN AND | All types except BLOB, MEDIUMBLOB, JSON and GEOMETRY | Closed interval comparison |
| 7 | IN | All types except BLOB, MEDIUMBLOB, and JSON; the primary key (timestamp) is also not supported | Equal to any value in the list |
| 8 | LIKE | BINARY, NCHAR, and VARCHAR | Wildcard match |
| 9 | MATCH, NMATCH | BINARY, NCHAR, and VARCHAR | Regular expression match |
......
docs/en/12-taos-sql/29-changes.md
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......@@ -18,6 +18,7 @@ description: This document describes how TDengine SQL has changed in version 3.0
| 8 | Mixed operations | Enhanced | Mixing scalar and vector operations in queries has been enhanced and is supported in all SELECT clauses.
| 9 | Tag operations | Added | Tag columns can be used in queries and clauses like data columns.
| 10 | Timeline clauses and time functions in supertables | Enhanced | When PARTITION BY is not used, data in supertables is merged into a single timeline.
| 11 | GEOMETRY | Added | Geometry
## SQL Syntax
......
docs/zh/12-taos-sql/01-data-type.md
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......@@ -42,12 +42,21 @@ CREATE DATABASE db_name PRECISION 'ns';
| 14 | NCHAR | 自定义 | 记录包含多字节字符在内的字符串，如中文字符。每个 NCHAR 字符占用 4 字节的存储空间。字符串两端使用单引号引用，字符串内的单引号需用转义字符 `\'`。NCHAR 使用时须指定字符串大小，类型为 NCHAR(10) 的列表示此列的字符串最多存储 10 个 NCHAR 字符。如果用户字符串长度超出声明长度，将会报错。 |
| 15 | JSON | | JSON 数据类型， 只有 Tag 可以是 JSON 格式 |
| 16 | VARCHAR | 自定义 | BINARY 类型的别名 |
| 17 | GEOMETRY | 自定义 | 几何类型 |
:::note
- 表的每行长度不能超过 48KB（从 3.0.5.0 版本开始为 64KB）（注意：每个 BINARY/NCHAR 类型的列还会额外占用 2 个字节的存储位置）。
- 表的每行长度不能超过 48KB（从 3.0.5.0 版本开始为 64KB）（注意：每个 BINARY/NCHAR/GEOMETRY 类型的列还会额外占用 2 个字节的存储位置）。
- 虽然 BINARY 类型在底层存储上支持字节型的二进制字符，但不同编程语言对二进制数据的处理方式并不保证一致，因此建议在 BINARY 类型中只存储 ASCII 可见字符，而避免存储不可见字符。多字节的数据，例如中文字符，则需要使用 NCHAR 类型进行保存。如果强行使用 BINARY 类型保存中文字符，虽然有时也能正常读写，但并不带有字符集信息，很容易出现数据乱码甚至数据损坏等情况。
- BINARY 类型理论上最长可以有 16,374（从 3.0.5.0 版本开始，数据列为 65,517，标签列为 16,382） 字节。BINARY 仅支持字符串输入，字符串两端需使用单引号引用。使用时须指定大小，如 BINARY(20) 定义了最长为 20 个单字节字符的字符串，每个字符占 1 字节的存储空间，总共固定占用 20 字节的空间，此时如果用户字符串超出 20 字节将会报错。对于字符串内的单引号，可以用转义字符反斜线加单引号来表示，即 `\'`。
- GEOMETRY 类型数据列为最大长度为 65,517 字节，标签列最大长度为 16,382 字节。支持 2D 的 POINT、LINESTRING 和 POLYGON 子类型数据。长度计算方式如下表所示：
| # | **语法** | **最小长度** | **最大长度** | **每组坐标长度增长** |
|---|--------------------------------------|----------|------------|--------------|
| 1 | POINT(1.0 1.0) | 21 | 21 | 无 |
| 2 | LINESTRING(1.0 1.0, 2.0 2.0) | 9+2*16 | 9+4094*16 | +16 |
| 3 | POLYGON((1.0 1.0, 2.0 2.0, 1.0 1.0)) | 13+3*16 | 13+4094*16 | +16 |
- SQL 语句中的数值类型将依据是否存在小数点，或使用科学计数法表示，来判断数值类型是否为整型或者浮点型，因此在使用时要注意相应类型越界的情况。例如，9999999999999999999 会认为超过长整型的上边界而溢出，而 9999999999999999999.0 会被认为是有效的浮点数。
:::
......
docs/zh/12-taos-sql/03-table.md
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......@@ -43,9 +43,9 @@ table_option: {
1. 表的第一个字段必须是 TIMESTAMP，并且系统自动将其设为主键；
2. 表名最大长度为 192；
3. 表的每行长度不能超过 48KB（从 3.0.5.0 版本开始为 64KB）;（注意：每个 BINARY/NCHAR 类型的列还会额外占用 2 个字节的存储位置）
3. 表的每行长度不能超过 48KB（从 3.0.5.0 版本开始为 64KB）;（注意：每个 BINARY/NCHAR/GEOMETRY 类型的列还会额外占用 2 个字节的存储位置）
4. 子表名只能由字母、数字和下划线组成，且不能以数字开头，不区分大小写
5. 使用数据类型 binary 或 nchar，需指定其最长的字节数，如 binary(20)，表示 20 字节；
5. 使用数据类型 BINARY/NCHAR/GEOMETRY，需指定其最长的字节数，如 BINARY(20)，表示 20 字节；
6. 为了兼容支持更多形式的表名，TDengine 引入新的转义符 "\`"，可以让表名与关键词不冲突，同时不受限于上述表名称合法性约束检查。但是同样具有长度限制要求。使用转义字符以后，不再对转义字符中的内容进行大小写统一。
例如：\`aBc\` 和 \`abc\` 是不同的表名，但是 abc 和 aBc 是相同的表名。
需要注意的是转义字符中的内容必须是可打印字符。
......
docs/zh/12-taos-sql/16-operators.md
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......@@ -39,7 +39,7 @@ TDengine 支持 `UNION ALL` 和 `UNION` 操作符。UNION ALL 将查询返回的
| 3 | \>, < | 除 BLOB、MEDIUMBLOB 和 JSON 外的所有类型 | 大于，小于 |
| 4 | \>=, <= | 除 BLOB、MEDIUMBLOB 和 JSON 外的所有类型 | 大于等于，小于等于 |
| 5 | IS [NOT] NULL | 所有类型 | 是否为空值 |
| 6 | [NOT] BETWEEN AND | 除 BOOL、BLOB、MEDIUMBLOB 和 JSON 外的所有类型 | 闭区间比较 |
| 6 | [NOT] BETWEEN AND | 除 BOOL、BLOB、MEDIUMBLOB、JSON 和 GEOMETRY 外的所有类型 | 闭区间比较 |
| 7 | IN | 除 BLOB、MEDIUMBLOB 和 JSON 外的所有类型，且不可以为表的时间戳主键列 | 与列表内的任意值相等 |
| 8 | LIKE | BINARY、NCHAR 和 VARCHAR | 通配符匹配 |
| 9 | MATCH, NMATCH | BINARY、NCHAR 和 VARCHAR | 正则表达式匹配 |
......
docs/zh/12-taos-sql/29-changes.md
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......@@ -18,6 +18,7 @@ description: "TDengine 3.0 版本的语法变更说明"
| 8 | 混合运算 | 增强 | 查询中的混合运算（标量运算和矢量运算混合）全面增强，SELECT的各个子句均全面支持符合语法语义的混合运算。
| 9 | 标签运算 | 新增 |在查询中，标签列可以像普通列一样参与各种运算，用于各种子句。
| 10 | 时间线子句和时间函数用于超级表查询 | 增强 |没有PARTITION BY时，超级表的数据会被合并成一条时间线。
| 11 | GEOMETRY | 新增 | 几何类型。
## SQL 语句变更
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