MySql-Mysql技术内幕~SQL编程学习笔记（N）

1、_rowid

类似Oracle的rowid

mysql> select _rowid rowid,t.* from city t limit ;
+-------+----+----------------+-------------+---------------+------------+
| rowid | ID | Name           | CountryCode | District      | Population |
+-------+----+----------------+-------------+---------------+------------+
|      |   | Kabul          | AFG         | Kabol         |     |
|      |   | Qandahar       | AFG         | Qandahar      |      |
|      |   | Herat          | AFG         | Herat         |      |
|      |   | Mazar-e-Sharif | AFG         | Balkh         |      |
|      |   | Amsterdam      | NLD         | Noord-Holland |      |
|      |   | Rotterdam      | NLD         | Zuid-Holland  |      |
|      |   | Haag           | NLD         | Zuid-Holland  |      |
|      |   | Utrecht        | NLD         | Utrecht       |      |
|      |   | Eindhoven      | NLD         | Noord-Brabant |      |
|     |  | Tilburg        | NLD         | Noord-Brabant |      |
+-------+----+----------------+-------------+---------------+------------+
rows in set (0.00 sec)
 
mysql>

2、查看表结构

mysql> show create table t\G;
*************************** . row ***************************
       Table: t
Create Table: CREATE TABLE `t` (
  `a` int() unsigned DEFAULT NULL,
  `b` int() unsigned DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8
 row in set (0.00 sec)
 
ERROR:
No query specified
 
mysql> desc t;
+-------+------------------+------+-----+---------+-------+
| Field | Type             | Null | Key | Default | Extra |
+-------+------------------+------+-----+---------+-------+
| a     | int() unsigned | YES  |     | NULL    |       |
| b     | int() unsigned | YES  |     | NULL    |       |
+-------+------------------+------+-----+---------+-------+
 rows in set (0.00 sec)
 
mysql>

3、hex函数

4、SQL_MODE：SQL模式

5、MySQL中的函数

1》cast：强制转换

2》