MYSQL數據表操作語句

1.查看某數據庫中的表

SHOW [FULL] TABLES [FROM db_name] [LIKE 'pattern']

SHOW TABLES列舉了給定數據庫中的非TEMPORARY表。也可以使用mysqlshow db_name命令得到此清單。

本命令也列舉數據庫中的其它視圖。支持FULL修改符，這樣SHOW FULL TABLES就可以顯示第二個輸出列。對於一個表，第二列的值為BASE TABLE；對於一個視圖，第二列的值為VIEW。

2.查看數據表的詳細信息

SHOW TABLE STATUS [FROM db_name] [LIKE 'pattern']

3.查看建表語句

SHOW CREATE TABLE tbl_name

4.建表語句

 

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

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    [(create_definition,...)]
    [table_options]
    [partition_options]
    [IGNORE | REPLACE]
    [AS] query_expression

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    { LIKE old_tbl_name | (LIKE old_tbl_name) }

建表語句內容比較多，先來一張圖看看整體結構。

在創建表格時，您可以使用TEMPORARY關鍵詞。只有在當前連接情況下，TEMPORARY表才是可見的。當連接關閉時，TEMPORARY表被自動取消。這意味着兩個不同的連接可以使用相同的臨時表名稱，同時兩個臨時表不會互相沖突，也不與原有的同名的非臨時表沖突。（原有的表被隱藏，直到臨時表被取消時為止。）您必須擁有CREATE TEMPORARY TABLES權限，才能創建臨時表。

create_definition:
    --列名 列定義
    col_name column_definition 
    --主鍵約束（主鍵索引）
  | [CONSTRAINT [symbol]] PRIMARY KEY [index_type] (index_col_name,...)
      [index_option] ...
  | {INDEX|KEY} [index_name] [index_type] (index_col_name,...)
      [index_option] ...
   --唯一約束 
  | [CONSTRAINT [symbol]] UNIQUE [INDEX|KEY]
      [index_name] [index_type] (index_col_name,...)
      [index_option] ...
  | {FULLTEXT|SPATIAL} [INDEX|KEY] [index_name] (index_col_name,...)
      [index_option] ...
   --外鍵約束 
  | [CONSTRAINT [symbol]] FOREIGN KEY
      [index_name] (index_col_name,...) reference_definition
  --自定義檢查約束  
  | CHECK (expr)

 

列定義

column_definition:
    data_type [NOT NULL | NULL] [DEFAULT default_value]
      [AUTO_INCREMENT] [UNIQUE [KEY] | [PRIMARY] KEY]
      [COMMENT 'string']
      [COLUMN_FORMAT {FIXED|DYNAMIC|DEFAULT}]
      [STORAGE {DISK|MEMORY|DEFAULT}]
      [reference_definition]
  | data_type [GENERATED ALWAYS] AS (expression)
      [VIRTUAL | STORED] [UNIQUE [KEY]] [COMMENT comment]
      [NOT NULL | NULL] [[PRIMARY] KEY]

1）一個整數列可以擁有一個附加屬性AUTO_INCREMENT。當您向一個已編入索引的AUTO_INCREMENT列中插入一個NULL值（建議）或0時，此列被設置為下一個序列的值。通常情況下為value+1，此處value是當前在表中的列的最大值。AUTO_INCREMENT序列從1開始。為了讓MySQL與部分ODBC應用軟件相兼容，您可以使用以下查詢方法找到最后一個插入行的AUTO_INCREMENT值：SELECT * FROM tbl_name WHERE auto_col IS NULL。

2）DEFAULT子句用於為列指定一個默認值。默認值必須為一個常數，不能為一個函數或一個表達式，有一種情況例外。例如，一個日期列的默認值不能被設置為一個函數，如NOW()或CURRENT_DATE。不過，有一種例外，您可以對TIMESTAMP列指定CURRENT_TIMESTAMP為默認值。BLOB和TEXT列不能被賦予默認值。

3）對於列的評注可以使用COMMENT選項來進行指定。評注通過SHOW CREATE TABLE和SHOW FULL COLUMNS語句顯示。

4）在UNIQUE索引中，所有的值必須互不相同。

5）PRIMARY KEY是一個唯一KEY，一個表只有一個PRIMARY KEY。PRIMARY KEY可以是一個多列索引。但是，在列規約中使用PRIMARY KEY關鍵字屬性無法創建多列索引。這么做只能把一個列標記為主列。您必須使用一個單獨的PRIMARY KEY（index_col_name, ...）子句。

 

 

實數據類型

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
  | spatial_type

索引與約束

 

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

index_type:
    USING {BTREE | HASH}

index_option:
    KEY_BLOCK_SIZE [=] value
  | index_type
  | WITH PARSER parser_name
  | COMMENT 'string'

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

 

 表基本屬性設置

 

table_options:
    table_option [[,] table_option] ...

table_option:
    ENGINE [=] engine_name
  | AUTO_INCREMENT [=] value
  | AVG_ROW_LENGTH [=] value
  | [DEFAULT] CHARACTER SET [=] charset_name
  | CHECKSUM [=] {0 | 1}
  | [DEFAULT] COLLATE [=] collation_name
  | COMMENT [=] 'string'
  | COMPRESSION [=] {'ZLIB'|'LZ4'|'NONE'}
  | CONNECTION [=] 'connect_string'
  | DATA DIRECTORY [=] 'absolute path to directory'
  | DELAY_KEY_WRITE [=] {0 | 1}
  | ENCRYPTION [=] {'Y' | 'N'}
  | INDEX DIRECTORY [=] 'absolute path to directory'
  | INSERT_METHOD [=] { NO | FIRST | LAST }
  | KEY_BLOCK_SIZE [=] value
  | MAX_ROWS [=] value
  | MIN_ROWS [=] value
  | PACK_KEYS [=] {0 | 1 | DEFAULT}
  | PASSWORD [=] 'string'
  | ROW_FORMAT [=] {DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT}
  | STATS_AUTO_RECALC [=] {DEFAULT|0|1}
  | STATS_PERSISTENT [=] {DEFAULT|0|1}
  | STATS_SAMPLE_PAGES [=] value
  | TABLESPACE tablespace_name
  | UNION [=] (tbl_name[,tbl_name]...)

 

 

 

表分區：

 

partition_options:
    PARTITION BY
        { [LINEAR] HASH(expr)
        | [LINEAR] KEY [ALGORITHM={1|2}] (column_list)
        | RANGE{(expr) | COLUMNS(column_list)}
        | LIST{(expr) | COLUMNS(column_list)} }
    [PARTITIONS num]
    [SUBPARTITION BY
        { [LINEAR] HASH(expr)
        | [LINEAR] KEY [ALGORITHM={1|2}] (column_list) }
      [SUBPARTITIONS num]
    ]
    [(partition_definition [, partition_definition] ...)]

partition_definition:
    PARTITION partition_name
        [VALUES
            {LESS THAN {(expr | value_list) | 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]
        [(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]

 

依據某個查詢建立新表：

 

query_expression:
    SELECT ...   (Some valid select or union statement)

 

對建表舉例：

 

CREATE TABLE `students` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `stu_num` varchar(30) NOT NULL,
  `stu_name` varchar(30) NOT NULL,
  `sex` enum('M','F') DEFAULT 'M',
  `major` varchar(50) DEFAULT NULL,
  `grade` tinyint(4) DEFAULT NULL,
  --主鍵
  PRIMARY KEY (`id`),
  --唯一約束
  UNIQUE KEY `stu_num` (`stu_num`)
)
--指定存儲引擎和字符集
ENGINE=InnoDB DEFAULT CHARSET=utf8;

 

依據某個查詢建立新表：

 

CREATE TABLE students_clone SELECT * FROM students;

 

按照此方式建立的students_clone表表結構將與students一致，且數據一致。

 

CREATE TABLE students_clone_1 LIKE students;

 

按照此方式建立的students_clone表表結構將與students一致，新建的數據表為空。

5.刪除數據表

 

DROP [TEMPORARY] TABLE [IF EXISTS] tbl_name [, tbl_name]

 

DROP TABLE用於取消一個或多個表。您必須有每個表的DROP權限。所有的表數據和表定義會被取消，所以使用本語句要小心。

 

6.清空表數據

 

TRUNCATE [TABLE] tbl_name

 

TRUNCATE TABLE用於完全清空一個表。