title | summary | category |
---|---|---|
CREATE TABLE | TiDB SQL Statement Reference |
An overview of the usage of CREATE TABLE for the TiDB database. |
reference |
This statement creates a new table in the currently selected database. See also CREATE TABLE LIKE
, which is documented separately.
CreateTableStmt:
IfNotExists:
TableName:
TableElementListOpt:
TableElement:
PartitionOpt:
ColumnDef:
ColumnName:
Type:
ColumnOptionListOpt:
TableOptionListOpt:
The CREATE TABLE
statement is used to create a table. Currently, it does not support temporary tables, CHECK
constraints, or importing data from other tables while creating tables. It supports some of the Partition_options
in syntax.
Here are some options about the CREATE TABLE
syntax:
CREATE TABLE [IF NOT EXISTS] tbl_name
(create_definition,...)
[table_options]
When you create an existing table, if you specify IF NOT EXIST
, it does not report an error. Otherwise, it reports an error.
CREATE TABLE [IF NOT EXISTS] tbl_name
{ LIKE old_tbl_name | (LIKE old_tbl_name) }
Use LIKE
to create an empty table based on the definition of another table including its column and index properties.
create_definition:
col_name column_definition
| [CONSTRAINT [symbol]] PRIMARY KEY [index_type] (index_col_name,...)
[index_option] ...
| {INDEX|KEY} [index_name] [index_type] (index_col_name,...)
[index_option] ...
| [CONSTRAINT [symbol]] UNIQUE [INDEX|KEY]
[index_name] [index_type] (index_col_name,...)
[index_option] ...
| {FULLTEXT} [INDEX|KEY] [index_name] (index_col_name,...)
[index_option] ...
| [CONSTRAINT [symbol]] FOREIGN KEY
[index_name] (index_col_name,...) reference_definition
The FULLTEXT
and FOREIGN KEY
in create_definition
are currently only supported in syntax.
column_definition:
data_type [NOT NULL | NULL] [DEFAULT default_value]
[AUTO_INCREMENT | AUTO_RANDOM [(length)]]
[UNIQUE [KEY] | [PRIMARY] KEY]
[COMMENT 'string']
[reference_definition]
| data_type [GENERATED ALWAYS] AS (expression)
[VIRTUAL | STORED] [UNIQUE [KEY]] [COMMENT comment]
[NOT NULL | NULL] [[PRIMARY] KEY]
data_type:
BIT[(length)]
| TINYINT[(length)] [UNSIGNED] [ZEROFILL]
| SMALLINT[(length)] [UNSIGNED] [ZEROFILL]
| MEDIUMINT[(length)] [UNSIGNED] [ZEROFILL]
| INT[(length)] [UNSIGNED] [ZEROFILL]
| INTEGER[(length)] [UNSIGNED] [ZEROFILL]
| BIGINT[(length)] [UNSIGNED] [ZEROFILL]
| REAL[(length,decimals)] [UNSIGNED] [ZEROFILL]
| DOUBLE[(length,decimals)] [UNSIGNED] [ZEROFILL]
| FLOAT[(length,decimals)] [UNSIGNED] [ZEROFILL]
| DECIMAL[(length[,decimals])] [UNSIGNED] [ZEROFILL]
| NUMERIC[(length[,decimals])] [UNSIGNED] [ZEROFILL]
| DATE
| TIME[(fsp)]
| TIMESTAMP[(fsp)]
| DATETIME[(fsp)]
| YEAR
| CHAR[(length)] [BINARY]
[CHARACTER SET charset_name] [COLLATE collation_name]
| VARCHAR(length) [BINARY]
[CHARACTER SET charset_name] [COLLATE collation_name]
| BINARY[(length)]
| VARBINARY(length)
| TINYBLOB
| BLOB
| MEDIUMBLOB
| LONGBLOB
| TINYTEXT [BINARY]
[CHARACTER SET charset_name] [COLLATE collation_name]
| TEXT [BINARY]
[CHARACTER SET charset_name] [COLLATE collation_name]
| MEDIUMTEXT [BINARY]
[CHARACTER SET charset_name] [COLLATE collation_name]
| LONGTEXT [BINARY]
[CHARACTER SET charset_name] [COLLATE collation_name]
| ENUM(value1,value2,value3,...)
[CHARACTER SET charset_name] [COLLATE collation_name]
| SET(value1,value2,value3,...)
[CHARACTER SET charset_name] [COLLATE collation_name]
| JSON
For the data_type
, see Data Types.
index_col_name:
col_name [(length)] [ASC | DESC]
The [ASC | DESC]
in index_col_name
is currently only supported in syntax.
index_type:
USING {BTREE | HASH}
The index_type
is currently only supported in syntax.
index_option:
KEY_BLOCK_SIZE [=] value
| index_type
| COMMENT 'string'
The KEY_BLOCK_SIZE
in index_option
is currently only supported in syntax.
reference_definition:
REFERENCES tbl_name (index_col_name,...)
[MATCH FULL | MATCH PARTIAL | MATCH SIMPLE]
[ON DELETE reference_option]
[ON UPDATE reference_option]
reference_option:
RESTRICT | CASCADE | SET NULL | NO ACTION | SET DEFAULT
table_options:
table_option [[,] table_option] ...
table_option:
AUTO_INCREMENT [=] value
| AVG_ROW_LENGTH [=] value
| SHARD_ROW_ID_BITS [=] value
| PRE_SPLIT_REGIONS [=] value
| [DEFAULT] CHARACTER SET [=] charset_name
| CHECKSUM [=] {0 | 1}
| [DEFAULT] COLLATE [=] collation_name
| COMMENT [=] 'string'
| COMPRESSION [=] {'ZLIB'|'LZ4'|'NONE'}
| CONNECTION [=] 'connect_string'
| DELAY_KEY_WRITE [=] {0 | 1}
| ENGINE [=] engine_name
| KEY_BLOCK_SIZE [=] value
| MAX_ROWS [=] value
| MIN_ROWS [=] value
| ROW_FORMAT [=] {DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT}
| STATS_PERSISTENT [=] {DEFAULT|0|1}
The table_option
currently only supports AUTO_INCREMENT
, SHARD_ROW_ID_BITS
(see TiDB Specific System Variables for details), PRE_SPLIT_REGIONS
, CHARACTER SET
, COLLATE
, and COMMENT
, while the others are only supported in syntax. The clauses are separated by a comma ,
. See the following table for details:
Parameters | Description | Example |
---|---|---|
AUTO_INCREMENT |
The initial value of the increment field | AUTO_INCREMENT = 5 |
SHARD_ROW_ID_BITS |
To set the number of bits for the implicit _tidb_rowid shards |
SHARD_ROW_ID_BITS = 4 |
PRE_SPLIT_REGIONS |
To pre-split 2^(PRE_SPLIT_REGIONS) Regions when creating a table |
PRE_SPLIT_REGIONS = 4 |
CHARACTER SET |
To specify the string code for the table; currently only support UTF8MB4 | CHARACTER SET = 'utf8mb4' |
COMMENT |
The comment information | COMMENT = 'comment info' |
The split-table
configuration option is enabled by default. When it is enabled, a separate Region is created for each newly created table.
mysql> CREATE TABLE t1 (a int);
Query OK, 0 rows affected (0.11 sec)
mysql> CREATE TABLE t2 LIKE t1;
Query OK, 0 rows affected (0.10 sec)
mysql> DESC t1;
+-------+---------+------+------+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+------+---------+-------+
| a | int(11) | YES | | NULL | |
+-------+---------+------+------+---------+-------+
1 row in set (0.00 sec)
mysql> INSERT INTO t1 VALUES (1);
Query OK, 1 row affected (0.02 sec)
mysql> SELECT * FROM t1;
+------+
| a |
+------+
| 1 |
+------+
1 row in set (0.00 sec)
- TiDB does not support the syntax
CREATE TEMPORARY TABLE
. - All of the data types except spatial types are supported.
FULLTEXT
,HASH
andSPATIAL
indexes are not supported.- The
KEY_BLOCK_SIZE
andENGINE
attributes are parsed but ignored. - The
index_col_name
attribute supports the length option with a maximum length limit of 3072 bytes. The length limit does not change depending on the storage engine, and character set used when building the table. - The
index_col_name
attribute supports the index sorting options ofASC
andDESC
- The
COMMENT
attribute supports a maximum of 1024 characters and does not support theWITH PARSER
option. - TiDB supports at most 512 columns in a single table. The corresponding number limit in InnoDB is 1017, and the hard limit in MySQL is 4096.