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CREATE TABLE
=================================
描述
-----------
该语句用来在数据库中创建一张新表。
格式
-----------
```javascript
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] table_name
(table_definition_list) [table_option_list] [partition_option] [AS] select;
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] table_name
LIKE table_name;
table_definition_list:
table_definition [, table_definition ...]
table_definition:
column_definition
| [CONSTRAINT [constraint_name]] PRIMARY KEY index_desc
| [CONSTRAINT [constraint_name]] UNIQUE {INDEX | KEY} [index_name] index_desc
| {INDEX | KEY} [index_name] index_desc
| FULLTEXT [INDEX | KEY] [index_name] fulltext_index_desc
column_definition_list:
column_definition [, column_definition ...]
column_definition:
column_name data_type
[DEFAULT const_value] [AUTO_INCREMENT]
[NULL | NOT NULL] [[PRIMARY] KEY] [UNIQUE [KEY]] comment
index_desc:
(column_desc_list) [index_type] [index_option_list]
fulltext_index_desc:
(column_desc_list) CTXCAT(column_desc_list) [index_option_list]
column_desc_list:
column_desc [, column_desc ...]
column_desc:
column_name [(length)] [ASC | DESC]
index_type:
USING BTREE
index_option_list:
index_option [ index_option ...]
index_option:
[GLOBAL | LOCAL]
| block_size
| compression
| STORING(column_name_list)
| comment
table_option_list:
table_option [ table_option ...]
table_option:
[DEFAULT] {CHARSET | CHARACTER SET} [=] charset_name
| [DEFAULT] COLLATE [=] collation_name
| primary_zone
| replica_num
| table_tablegroup
| block_size
| compression
| AUTO_INCREMENT [=] INT_VALUE
| comment
| DUPLICATE_SCOPE [=] "none|cluster"
| LOCALITY [=] "locality description"
| ROW_FORMAT [=] REDUNDANT|COMPACT|DYNAMIC|COMPRESSED|DEFAULT
| PCTFREE [=] num
| parallel_clause
parallel_clause:
{NOPARALLEL | PARALLEL integer}
partition_option:
PARTITION BY HASH(expression)
[subpartition_option] PARTITIONS partition_count
| PARTITION BY KEY([column_name_list])
[subpartition_option] PARTITIONS partition_count
| PARTITION BY RANGE {(expression) | COLUMNS (column_name_list)}
[subpartition_option] (range_partition_list)
| PARTITION BY LIST {(expression) | COLUMNS (column_name_list)}
[subpartition_option] PARTITIONS partition_count
subpartition_option:
SUBPARTITION BY HASH(expression)
SUBPARTITIONS subpartition_count
| SUBPARTITION BY KEY(column_name_list)
SUBPARTITIONS subpartition_count
| SUBPARTITION BY RANGE {(expression) | COLUMNS (column_name_list)}
(range_subpartition_list)
| SUBPARTITION BY LIST(expression)
range_partition_list:
range_partition [, range_partition ...]
range_partition:
PARTITION partition_name
VALUES LESS THAN {(expression_list) | MAXVALUE}
range_subpartition_list:
range_subpartition [, range_subpartition ...]
range_subpartition:
SUBPARTITION subpartition_name
VALUES LESS THAN {(expression_list) | MAXVALUE}
expression_list:
expression [, expression ...]
column_name_list:
column_name [, column_name ...]
partition_name_list:
partition_name [, partition_name ...]
partition_count | subpartition_count:
INT_VALUE
```
参数说明
-------------
| **参数** | **描述** |
|--------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| DUPLICATE_SCOPE | 用来指定复制表属性，取值如下： * none：表示该表是一个普通表 * zone：表示该表是一个复制表，leader需要将事务复制到本zone的所有F副本及R副本 * region：表示该表是一个复制表，leader需要将事务复制到本region的所有F副本及R副本 * cluster：表示该表是一个复制表，leader需要将事务复掉到cluster的所有F副本及R副本 不指定DUPLICATE_SCOPE的情况下，默认值为none。 |
| ROW_FORMAT | 指定表是否开启encoding存储格式 * redundant <!-- --> <!-- --> * compact <!-- --> <!-- --> * dynamic <!-- --> <!-- --> * compressed <!-- --> <!-- --> * default <!-- --> |
| BLOCK_SIZE | 指定表的微块大小 |
| COMPRESSION | 指定表的压缩算法，取值如下： 1. none：不使用压缩算法 2. lz4_1.0: 使用lz4压缩算法 3. zstd_1.0: 使用zstd压缩算法 4. snappy_1.0: 使用snappy压缩算法 |
| CHARSET \| CHARACTER SET | 指定表中列的默认字符集，可使用：utf8, utf8mb4, gbk, utf16, gb18030 |
| COLLATE | 指定表中列的默认比较规则，可使用： utf8_bin, utf8_general_ci, utf8_unicode_ci, gbk_bin, gbk_chinese_ci, utf8mb4_general_ci, utf8mb4__general_cs, utf8mb4_bin, utf8mb4_unicode_ci, utf16_general_ci, utf16_bin, utf16_unicode_ci, gb18030_chinese_ci, gb18030_bin |
| primary_zone | 指定主Zone（副本Leader所在 Zone）。 |
| replica_num | 指定副本数。 |
| table_tablegroup | 指定表所属的talegroup。 |
| AUTO_INCREMENT | 指定表中自增列的初始值。 |
| comment | 注释。 |
| LOCALITY | 描述副本在Zone间的分布情况，如：F@z1,F@z2,F@z3,R@z4 表示z1, z2, z3为全功能副本，z4为只读副本。 |
| PCTFREE | 指定宏块保留空间百分比。 |
| parallel_clause | 指定表级别的并行度： * NOPARALLEL：并行度为1，默认配置 * PARALLEL integer：指定并行度，integer 取值大于等于 1。 |
举例
-----------
* 创建数据库表。
```javascript
CREATE TABLE test (c1 int primary key, c2 VARCHAR(50)) REPLICA_NUM = 3, PRIMARY_ZONE = 'zone1';
```
* 创建表，并指定垂直分区。其中第一个分区只有列 c3，第二个分区包含列 c1、c2，没有列出的 c4、c5 列为第三个分区。
```javascript
CREATE TABLE t1(c1 int,
c2 int,
c3 int,
c4 int,
c5 int)
PARTITION BY CLOUMN ( c3, (c1, c2));
```
* 创建一个复制表。
```javascript
CREATE TABLE item() locality = 'F,R{all_server}@hz1, F,R{all_server}@hz2,
F,R{all_server}@hz3' DUPLICATE_SCOPE="cluster"
```
* 创建带索引的表。
```javascript
create table t1 (c1 int primary key, c2 int, c3 int, index i1 (c2));
```
* 创建 hash 分区，分区数为 8 的表。
```javascript
create table t1 (c1 int primary key, c2 int) partition by hash(c1) partitions 8;
```
* 创建一级分区为 range 分区，二级分区为 key 分区的表。
```javascript
create table t1 (c1 int, c2 int, c3 int)
partition by range(c1) subpartition by key(c2, c3) subpartitions 5
(partition p0 values less than(0), partition p1 values less than(100));
```
* 创建一列为 gbk, 一列为 utf8 的表。
```javascript
create table t1 (c1 varchar(10),
c2 varchar(10) charset gbk collate gbk_bin)
default charset utf8 collate utf8mb4_general_ci;
```
* 开启 encoding 并使用 zstd 压缩，宏块保留空间为 5%。
```javascript
create table t1 (c1 int, c2 int, c3 varchar(64))
compression 'zstd_1.0'
ROW_FORMAT dynamic
pctfree 5;
```
* 创建表 t1，并设置并行度为 3。
```unknow
create table t1(c1 int primary key, c2 int) parallel 3;
```