Mysql基本操作系列二

　　表中添加字段　

mysql> alter table leaf add leaf_pri int(5);
Query OK, 4 rows affected (0.06 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> select * from leaf;
+---------+-----------+----------+----------+----------+------------+----------+

| leaf_id | leaf_name | leaf_age | leaf_sal | leaf_sex | leaf_bir   | leaf_pri |

+---------+-----------+----------+----------+----------+------------+----------+

| 101     | leaf      |       24 |     8000 | male     | 2013-08-06 |     NULL |

| 102     | lea       |       34 |     7000 | male     | 2013-07-06 |     NULL |

| 103     | le        |       20 |     6000 | male     | 2013-06-06 |     NULL |

| 104     | l         |       10 |     5000 | male     | 2013-05-06 |     NULL |

+---------+-----------+----------+----------+----------+------------+----------+

　　新添加字段赋值

mysql> update leaf set leaf_pri="100";
Query OK, 4 rows affected (0.06 sec)
Rows matched: 4  Changed: 4  Warnings: 0

mysql> select * from leaf;
+---------+-----------+----------+----------+----------+------------+----------+

| leaf_id | leaf_name | leaf_age | leaf_sal | leaf_sex | leaf_bir   | leaf_pri |

+---------+-----------+----------+----------+----------+------------+----------+

| 101     | leaf      |       24 |     8000 | male     | 2013-08-06 |      100 |

| 102     | lea       |       34 |     7000 | male     | 2013-07-06 |      100 |

| 103     | le        |       20 |     6000 | male     | 2013-06-06 |      100 |

| 104     | l         |       10 |     5000 | male     | 2013-05-06 |      100 |

+---------+-----------+----------+----------+----------+------------+----------+

4 rows in set (0.00 sec)

　　两字段数据相加

mysql> select leaf_name,leaf_sal,leaf_pri,leaf_sal+leaf_pri from leaf;
+-----------+----------+----------+-------------------+
| leaf_name | leaf_sal | leaf_pri | leaf_sal+leaf_pri |
+-----------+----------+----------+-------------------+
| leaf      |     8000 |      100 |              8100 |
| lea       |     7000 |      100 |              7100 |
| le        |     6000 |      100 |              6100 |
| l         |     5000 |      100 |              5100 |
+-----------+----------+----------+-------------------+

　　distinct 过滤重复, 必须使用列名

mysql> select distinct leaf_pri from leaf;
+----------+
| leaf_pri |
+----------+
|      100 |
+----------+
1 row in set (0.00 sec)

mysql> select distinct leaf_name,leaf_pri from leaf;
+-----------+----------+
| leaf_name | leaf_pri |
+-----------+----------+
| leaf      |      100 |
| lea       |      100 |
| le        |      100 |
| l         |      100 |
+-----------+----------+
4 rows in set (0.00 sec)

　　选取表中leaf_sex=male的人

mysql> select leaf_id,leaf_name,leaf_sex from leaf where leaf_sex='male';
+---------+-----------+----------+
| leaf_id | leaf_name | leaf_sex |
+---------+-----------+----------+
| 101     | leaf      | male     |
| 102     | lea       | male     |
| 103     | le        | male     |
| 104     | l         | male     |
| 105     | leaf      | male     |
| 106     | lea       | male     |
| 107     | lea       | male     |
+---------+-----------+----------+
7 rows in set (0.00 sec)

　　选取表中leaf_pri=200的人

mysql> select leaf_id,leaf_name,leaf_pri from leaf where leaf_pri=200;
+---------+-----------+----------+
| leaf_id | leaf_name | leaf_pri |
+---------+-----------+----------+
| 105     | leaf      |      200 |
| 106     | lea       |      200 |
| 107     | lea       |      200 |
+---------+-----------+----------+
3 rows in set (0.00 sec)　　

　　between and 表示一个范围,选取的是两端的闭区间

mysql> select leaf_name,leaf_sal from leaf where leaf_sal between 7000 and 8000;

+-----------+----------+
| leaf_name | leaf_sal |
+-----------+----------+
| leaf      |     8000 |
| lea       |     7000 |
| lea       |     8000 |
+-----------+----------+
3 rows in set (0.00 sec)

　　in 表示一个集合，是离散值。含义为等于其中任意一个值

mysql> select leaf_name,leaf_age from leaf where leaf_age in (20,24);
+-----------+----------+
| leaf_name | leaf_age |
+-----------+----------+
| leaf      |       24 |
| le        |       20 |
| leaf      |       20 |
| lea       |       20 |
| lea       |       24 |
+-----------+----------+
5 rows in set (0.00 sec)

mysql> select leaf_name,leaf_age from leaf where leaf_name in ('leaf','lea');
+-----------+----------+
| leaf_name | leaf_age |
+-----------+----------+
| leaf      |       24 |
| lea       |       34 |
| leaf      |       20 |
| lea       |       20 |
| lea       |       24 |
+-----------+----------+
5 rows in set (0.00 sec)

　　模糊查询

　　like和通配符进行查找        通配符的种类:　　1) %表0或者多个字符；   2) _表示任意单个字符

mysql> select leaf_name from leaf where leaf_name like '_ea%';
+-----------+
| leaf_name |
+-----------+
| leaf      |
| lea       |
| leaf      |
| lea       |
| lea       |
+-----------+
5 rows in set (0.00 sec)

　　高级检索

mysql> select leaf_name,leaf_sal,leaf_pri from leaf where leaf_sal>6000 and leaf
_name='leaf';
+-----------+----------+----------+
| leaf_name | leaf_sal | leaf_pri |
+-----------+----------+----------+
| leaf      |     8000 |      100 |
+-----------+----------+----------+
1 row in set (0.00 sec)

mysql> select leaf_name,leaf_sal,leaf_pri from leaf where leaf_sal>6000 and (lea
f_name='leaf' or leaf_pri=200);
+-----------+----------+----------+
| leaf_name | leaf_sal | leaf_pri |
+-----------+----------+----------+
| leaf      |     8000 |      100 |
| lea       |     8000 |      200 |
+-----------+----------+----------+
2 rows in set (0.00 sec)