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[例子类] "CREATE TABLE"语法及例子

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发表于 2007-7-26 15:00:23 | 显示全部楼层 |阅读模式
作者:kider

沉寂的列规格变更
(在有些情况下,较早版本的MySQL会静默地更改在CREATE TABLE或ALTER TABLE语句中给定的列规约。在MySQL 5.1中不会进行这类变更。如果使用指定的数据类型无法创建列,则会出现错误。)

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    [(create_definition,...)]
    [table_options] [select_statement]

或:

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    [(] LIKE old_tbl_name [)];


create_definition:
    column_definition
  | [CONSTRAINT [symbol]] PRIMARY KEY [index_type] (index_col_name,...)
  | KEY [index_name] [index_type] (index_col_name,...)
  | INDEX [index_name] [index_type] (index_col_name,...)
  | [CONSTRAINT [symbol]] UNIQUE [INDEX]
        [index_name] [index_type] (index_col_name,...)
  | [FULLTEXT|SPATIAL] [INDEX] [index_name] (index_col_name,...)
  | [CONSTRAINT [symbol]] FOREIGN KEY
        [index_name] (index_col_name,...) [reference_definition]
  | CHECK (expr)

column_definition:
    col_name type [NOT NULL | NULL] [DEFAULT default_value]
        [AUTO_INCREMENT] [UNIQUE [KEY] | [PRIMARY] KEY]
        [COMMENT 'string'] [reference_definition]

type:
    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
  | TIMESTAMP
  | DATETIME
  | CHAR(length) [BINARY | ASCII | UNICODE]
  | VARCHAR(length) [BINARY]
  | TINYBLOB
  | BLOB
  | MEDIUMBLOB
  | LONGBLOB
  | TINYTEXT [BINARY]
  | TEXT [BINARY]
  | MEDIUMTEXT [BINARY]
  | LONGTEXT [BINARY]
  | ENUM(value1,value2,value3,...)
  | SET(value1,value2,value3,...)
  | spatial_type

index_col_name:
    col_name [(length)] [ASC | DESC]

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

table_options: table_option [table_option] ...

table_option:
    {ENGINE|TYPE} = engine_name
  | AUTO_INCREMENT = value
  | AVG_ROW_LENGTH = value
  | [DEFAULT] CHARACTER SET charset_name [COLLATE collation_name]
  | CHECKSUM = {0 | 1}
  | COMMENT = 'string'
  | C
  | MAX_ROWS = value
  | MIN_ROWS = value
  | PACK_KEYS = {0 | 1 | DEFAULT}
  | PASSWORD = 'string'
  | DELAY_KEY_WRITE = {0 | 1}
  | ROW_FORMAT = {DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT}
  | UNION = (tbl_name[,tbl_name]...)
  | INSERT_METHOD = { NO | FIRST | LAST }
  | DATA DIRECTORY = 'absolute path to directory'
  | INDEX DIRECTORY = 'absolute path to directory'

partition_options:
    PARTITION BY
           [LINEAR] HASH(expr)
        |  [LINEAR] KEY(column_list)
        |  RANGE(expr)
        |  LIST(column_list)
    [PARTITIONS num]
    [  SUBPARTITION BY
           [LINEAR] HASH(expr)
         | [LINEAR] KEY(column_list)
      [SUBPARTITIONS(num)]  
    ]
    [(partition_definition), [(partition_definition)], ...]

partition_definition:
    PARTITION partition_name
        [VALUES {
                  LESS THAN (expr) | MAXVALUE
                | IN (value_list) }]
        [[STORAGE] ENGINE [=] engine-name]
        [COMMENT [=] 'comment_text' ]
        [DATA DIRECTORY [=] 'data_dir']
        [INDEX DIRECTORY [=] 'index_dir']
        [MAX_ROWS [=] max_number_of_rows]
        [MIN_ROWS [=] min_number_of_rows]
        [TABLESPACE [=] (tablespace_name)]
        [NODEGROUP [=] node_group_id]
        [(subpartition_definition), [(subpartition_definition)], ...]

subpartition_definition:
    SUBPARTITION logical_name
        [[STORAGE] ENGINE [=] engine-name]
        [COMMENT [=] 'comment_text' ]
        [DATA DIRECTORY [=] 'data_dir']
        [INDEX DIRECTORY [=] 'index_dir']
        [MAX_ROWS [=] max_number_of_rows]
        [MIN_ROWS [=] min_number_of_rows]
        [TABLESPACE [=] (tablespace_name)]
        [NODEGROUP [=] node_group_id]

select_statement:
    [IGNORE | REPLACE] [AS] SELECT ...   (Some legal select statement)
CREATE TABLE用于创建带给定名称的表。您必须拥有表CREATE权限。


例子:
部分复制表
1、已经有table1存在如下;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| a     | int(11)     | NO   | PRI | NULL    | auto_increment |
| b     | varchar(30) | YES  |     | NULL    |                |
| c     | varchar(50) | YES  |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+
3 rows in set (0.00 sec)

2、创建(复制)表
mysql> create table table2 select a, b as bb from table1;
Query OK, 6 rows affected (0.09 sec)
Records: 6  Duplicates: 0  Warnings: 0

3、结果
mysql> desc table2;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| a      | int(11)     | NO   |     | 0       |       |
| bb    | varchar(30) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
2 rows in set (0.00 sec)
数据也会有了
mysql> select * from table2;
+----+----------+
| a  | bb       |
+----+----------+
| 1 | ab       |
| 2 | bc       |
| 3 | ca       |
| 4 | s        |
| 5 | Ac       |
| 6 | Ba       |
+----+----------+
6 rows in set (0.00 sec)

[ 本帖最后由 kider 于 2007-7-26 15:38 编辑 ]
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