mysql_2

Posted 2020-09-28

--创建表
create [temporary] table [if not exists] tbl_name
    [( [column_definition],...|[index_definition])]
    [table_option] 
    [select_statement];
column_definition:
    col_name  type  
    [not null | null] 
    [default default_value]
    [auto_increment]--设置自增属性，只有整型列才能设置此属性。当插入NULL值或0到一个AUTO_INCREMENT列中时，列被设置为value+1，
                    --在这里value是此前表中该列的最大值。AUTO_INCREMENT顺序从1开始。每个表只能有一个AUTO_INCREMENT列，并且它必须被索引。
    [unique [key]|
    [primary] key]
    [comment ‘string‘]
    [reference_definition]
reference_definition:
    references tbl_name [(index_col_name,...)]
        [on delete  {restrict | cascade | set null | no action}]
        [on update  {restrict | cascade | set null | no action}]
index_definition:
    [constraint [symbol]]primary key [index_type] (index_col_name,...)        /*主键*/
    |{index | key} [index_name] [index_type] (index_col_name,...)                /*索引*/
    |[constraint [symbol]] unique [index] [index_name] [index_type] (index_col_name,...)/*唯一性索引*/
    |[fulltext|spatial] [index] [index_name] (index_col_name,...)            /*全文索引*/
    |[constraint [symbol]] foreign key  [index_name] (index_col_name,...) [reference_definition]/*外键*/
}]
table_option:
    {engine | type} = engine_name                /*存储引擎*/
    | auto_increment = value                    /*初始值*/
    | avg_row_length = value                    /*表的平均行长度*/
    | [default] character set charset_name [collate collation_name]    /*默认字符集和校对*/
    | checksum = {0 | 1}                        /*设置为1表示求校验和*/
    | comment = ‘string‘                        /*注释*/
    | connection = ‘connect_string‘                    /*连接字符串*/
    | max_rows = value                        /*行的最大数*/
    | min_rows = value                        /*列的最小数*/
    | pack_keys = {0 | 1 | default}
    | password = ‘string‘                        /*对.frm文件加密*/
    | delay_key_write = {0 | 1}                    /*对关键字的更新*/
    | row_format = {default|dynamic|fixed|compressed|redundant|compact}/*定义各行应如何储存*/
    | union = (tbl_name[,tbl_name]...)                /*表示哪个表应该合并*/
    | insert_method = { no | first | last }            /*是否执行insert语句*/
    | data directory = ‘absolute path to directory‘        /*数据文件的路径*/
    | index directory = ‘absolute path to directory‘    /*索引的路径*/
select_statement: