CREATE TABLE
This statement creates a new table in the currently selected database. It behaves similarly to the CREATE TABLE
statement in MySQL.
Synopsis
- CreateTableStmt
- IfNotExists
- TableName
- TableElementListOpt
- TableElementList
- TableElement
- ColumnDef
- ColumnOptionListOpt
- ColumnOptionList
- ColumnOption
- CreateTableOptionListOpt
- PartitionOpt
- DuplicateOpt
- TableOptionList
- TableOption
CreateTableStmt ::=
'CREATE' OptTemporary 'TABLE' IfNotExists TableName ( TableElementListOpt CreateTableOptionListOpt PartitionOpt DuplicateOpt AsOpt CreateTableSelectOpt | LikeTableWithOrWithoutParen )
IfNotExists ::=
('IF' 'NOT' 'EXISTS')?
TableName ::=
Identifier ('.' Identifier)?
TableElementListOpt ::=
( '(' TableElementList ')' )?
TableElementList ::=
TableElement ( ',' TableElement )*
TableElement ::=
ColumnDef
| Constraint
ColumnDef ::=
ColumnName ( Type | 'SERIAL' ) ColumnOptionListOpt
ColumnOptionListOpt ::=
ColumnOption*
ColumnOptionList ::=
ColumnOption*
ColumnOption ::=
'NOT'? 'NULL'
| 'AUTO_INCREMENT'
| PrimaryOpt 'KEY'
| 'UNIQUE' 'KEY'?
| 'DEFAULT' DefaultValueExpr
| 'SERIAL' 'DEFAULT' 'VALUE'
| 'ON' 'UPDATE' NowSymOptionFraction
| 'COMMENT' stringLit
| ConstraintKeywordOpt 'CHECK' '(' Expression ')' EnforcedOrNotOrNotNullOpt
| GeneratedAlways 'AS' '(' Expression ')' VirtualOrStored
| ReferDef
| 'COLLATE' CollationName
| 'COLUMN_FORMAT' ColumnFormat
| 'STORAGE' StorageMedia
| 'AUTO_RANDOM' OptFieldLen
CreateTableOptionListOpt ::=
TableOptionList?
PartitionOpt ::=
( 'PARTITION' 'BY' PartitionMethod PartitionNumOpt SubPartitionOpt PartitionDefinitionListOpt )?
DuplicateOpt ::=
( 'IGNORE' | 'REPLACE' )?
TableOptionList ::=
TableOption ( ','? TableOption )*
TableOption ::=
PartDefOption
| DefaultKwdOpt ( CharsetKw EqOpt CharsetName | 'COLLATE' EqOpt CollationName )
| ( 'AUTO_INCREMENT' | 'AUTO_ID_CACHE' | 'AUTO_RANDOM_BASE' | 'AVG_ROW_LENGTH' | 'CHECKSUM' | 'TABLE_CHECKSUM' | 'KEY_BLOCK_SIZE' | 'DELAY_KEY_WRITE' | 'SHARD_ROW_ID_BITS' | 'PRE_SPLIT_REGIONS' ) EqOpt LengthNum
| ( 'CONNECTION' | 'PASSWORD' | 'COMPRESSION' ) EqOpt stringLit
| RowFormat
| ( 'STATS_PERSISTENT' | 'PACK_KEYS' ) EqOpt StatsPersistentVal
| ( 'STATS_AUTO_RECALC' | 'STATS_SAMPLE_PAGES' ) EqOpt ( LengthNum | 'DEFAULT' )
| 'STORAGE' ( 'MEMORY' | 'DISK' )
| 'SECONDARY_ENGINE' EqOpt ( 'NULL' | StringName )
| 'UNION' EqOpt '(' TableNameListOpt ')'
| 'ENCRYPTION' EqOpt EncryptionOpt
The following table_options are supported. Other options such as AVG_ROW_LENGTH
, CHECKSUM
, COMPRESSION
, CONNECTION
, DELAY_KEY_WRITE
, ENGINE
, KEY_BLOCK_SIZE
, MAX_ROWS
, MIN_ROWS
, ROW_FORMAT
and STATS_PERSISTENT
are parsed but ignored.
Options | 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 |
AUTO_ID_CACHE | To set the auto ID cache size in a TiDB instance. By default, TiDB automatically changes this size according to allocation speed of auto ID | AUTO_ID_CACHE = 200 |
AUTO_RANDOM_BASE | To set the initial incremental part value of auto_random. This option can be considered as a part of the internal interface. Users can ignore this parameter | AUTO_RANDOM_BASE = 0 |
CHARACTER SET | To specify the character set for the table | CHARACTER SET = 'utf8mb4' |
COMMENT | The comment information | COMMENT = 'comment info' |
Examples
Creating a simple table and inserting one row:
CREATE TABLE t1 (a int);
DESC t1;
SHOW CREATE TABLE t1\G
INSERT INTO t1 (a) VALUES (1);
SELECT * FROM t1;
mysql> drop table if exists t1;
Query OK, 0 rows affected (0.23 sec)
mysql> CREATE TABLE t1 (a int);
Query OK, 0 rows affected (0.09 sec)
mysql> DESC t1;
+-------+---------+------+------+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+------+---------+-------+
| a | int(11) | YES | | NULL | |
+-------+---------+------+------+---------+-------+
1 row in set (0.00 sec)
mysql> SHOW CREATE TABLE t1\G
*************************** 1. row ***************************
Table: t1
Create Table: CREATE TABLE `t1` (
`a` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin
1 row in set (0.00 sec)
mysql> INSERT INTO t1 (a) VALUES (1);
Query OK, 1 row affected (0.03 sec)
mysql> SELECT * FROM t1;
+------+
| a |
+------+
| 1 |
+------+
1 row in set (0.00 sec)
Dropping a table if it exists, and conditionally creating a table if it does not exist:
DROP TABLE IF EXISTS t1;
CREATE TABLE IF NOT EXISTS t1 (
id BIGINT NOT NULL PRIMARY KEY auto_increment,
b VARCHAR(200) NOT NULL
);
DESC t1;
mysql> DROP TABLE IF EXISTS t1;
Query OK, 0 rows affected (0.22 sec)
mysql> CREATE TABLE IF NOT EXISTS t1 (
-> id BIGINT NOT NULL PRIMARY KEY auto_increment,
-> b VARCHAR(200) NOT NULL
-> );
Query OK, 0 rows affected (0.08 sec)
mysql> DESC t1;
+-------+--------------+------+------+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------------+------+------+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| b | varchar(200) | NO | | NULL | |
+-------+--------------+------+------+---------+----------------+
2 rows in set (0.00 sec)
MySQL compatibility
- TiDB does not support temporary tables. The
CREATE TEMPORARY TABLE
syntax will raise an error iftidb_enable_noop_functions = 0
; TiDB simply ignores theTEMPORARY
keyword iftidb_enable_noop_functions = 1
. - All of the data types except spatial types are supported.
FULLTEXT
,HASH
andSPATIAL
indexes are not supported.- For compatibility, the
index_col_name
attribute supports the length option with a maximum length limit of 3072 bytes by default. The length limit can be changed through themax-index-length
configuration option. For details, see TiDB configuration file. - The
[ASC | DESC]
inindex_col_name
is currently parsed but ignored (MySQL 5.7 compatible behavior). - The
COMMENT
attribute supports a maximum of 1024 characters and does not support theWITH PARSER
option. - TiDB supports 1017 columns in a single table by default and 4096 columns at most. The corresponding number limit in InnoDB is 1017 columns, and the hard limit in MySQL is 4096 columns. For details, see TiDB Limitations.
- For partitioned tables, only Range, Hash and Range Columns (single column) are supported. For details, see partitioned table.
CHECK
constraints are parsed but ignored (MySQL 5.7 compatible behavior). For details, see Constraints.FOREIGN KEY
constraints are parsed and stored, but not enforced by DML statements. For details, see Constraints.