In this option, if a value is given in an INSERT statement, it will be inserted. Otherwise, the value on the IDENTITY column will be generated automatically. CREATETABLEstudent(student_idINTGENERATEDBYDEFAULTASIDENTITY,student_name VARCHAR2(50));-- IDENTITY column gets the data automatically...
1. mysql> CREATE TABLE test (a INT NOT NULL AUTO_INCREMENT, 2. -> PRIMARY KEY (a), KEY(b)) 3. -> ENGINE=MyISAM SELECT b,c FROM test2; 1. 2. 3. 这将创建一个包含a、b和c三列的 MyISAM 表。ENGINE 选项是 CREATE TABLE 语句的一部分,不应在 SELECT 之后使用;这将导致语法错误。其...
Query OK,1rowaffected (0.10sec) auto_increment表示字段为整数或者浮点数类型的value+1递增数值,value为当前表中该字段最大的值,默认是从1开始递增;一个表中只容许有一个自增字段,且该字段必须有key属性,不能含有default属性,如果是负值会被当成很大的正数 column_format目前仅在ndb存储引擎的表上有用,表示该字...
[ ; ] <column_definition> ::= column_name <data_type> [ FILESTREAM ] [ COLLATE collation_name ] [ SPARSE ] [ MASKED WITH ( FUNCTION = 'mask_function' ) ] [ [ CONSTRAINT constraint_name ] DEFAULT constant_expression ] [ IDENTITY [ ( seed , increment ) ] ] [ NOT FOR REPLICATION ...
mysql> create table mytable (id int(4) not null primary key auto_increment,name char(10) not null,score decimal(5,2),address varchar(50) not null default '未知')engine=innodb; Query OK, 0 rows affected (0.01 sec) mysql> select * from mytable; ...
column_definition|[,|[CONSTRAINT[constraint_name]]{PRIMARYKEY|UNIQUE}(column_name)//在创建所有列后添加约束|[CONSTRAINT[constraint_name]]FOREIGNKEY(column_name,column_name...)references_clause constraint_state|[CONSTRAINT[constraint_name]]CHECK(expression)constraint_state]column_definition_list: column_...
| cust_id |int(11) | NO | PRI | NULL | auto_increment | | cust_name |char(50) | NO | | NULL | | | cust_address |char(50) | YES | | NULL | | | cust_city |char(50) | YES | | NULL | | | cust_state |char(5) | YES | | NULL | | ...
Transact-SQL 语法约定 语法 syntaxsql复制 -- Create a new table.CREATETABLE{database_name.schema_name.table_name|schema_name.table_name|table_name} ( {column_name<data_type>[<column_options>] } [ ,...n ] ) [WITH([ ,...n ] ) ] [;]<column_options>::=[COLLATEWindows_collation_...
在写诗的时候,有时需要我们去对比数据库的数据,验证数据的准确性,这时就需要用到SQL语句,部分查询语句你可以找开发要,开始的一些次数还可以,时间久了天天只能依赖别人是不是不大好?最好是自己会写查询SQL语句才是最棒的,提高自己的生存能力,前提是要有这个基础,所
[ ; ] <column_definition> ::= column_name <data_type> [ FILESTREAM ] [ COLLATE collation_name ] [ SPARSE ] [ MASKED WITH ( FUNCTION = 'mask_function' ) ] [ [ CONSTRAINT constraint_name ] DEFAULT constant_expression ] [ IDENTITY [ ( seed , increment ) ] ] [ NOT FOR REPLICATION ...