8、MySQL的数据检索

最新推荐文章于 2025-01-14 17:16:17 发布

原创最新推荐文章于 2025-01-14 17:16:17 发布 · 167 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#mysql

MySQL 专栏收录该内容

39 篇文章

订阅专栏

查看表结构

mysql> desc products;
+------------+--------------+------+-----+---------+-------+
| Field      | Type         | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| prod_id    | char(10)     | NO   | PRI | NULL    |       |
| vend_id    | int(11)      | NO   | MUL | NULL    |       |
| prod_name  | char(255)    | NO   |     | NULL    |       |
| prod_price | decimal(8,2) | NO   |     | NULL    |       |
| prod_desc  | text         | YES  |     | NULL    |       |
+------------+--------------+------+-----+---------+-------+

注释用#
distinct 唯一值

mysql> select distinct vend_id from products;
+---------+
| vend_id |
+---------+
|    1001 |
|    1002 |
|    1003 |
|    1005 |
+---------+

limit限定

mysql> select * from products limit 3;
+---------+---------+--------------+------------+----------------------------------------------------------------+
| prod_id | vend_id | prod_name    | prod_price | prod_desc                                                      |
+---------+---------+--------------+------------+----------------------------------------------------------------+
| ANV01   |    1001 | .5 ton anvil | 5.99       | .5 ton anvil, black, complete with handy hook                  |
| ANV02   |    1001 | 1 ton anvil  | 9.99       | 1 ton anvil, black, complete with handy hook and carrying case |
| ANV03   |    1001 | 2 ton anvil  | 14.99      | 2 ton anvil, black, complete with handy hook and carrying case |
+---------+---------+--------------+------------+----------------------------------------------------------------+
3 rows in set (0.06 sec)

limit分页

mysql> select * from products limit 3,3;
+---------+---------+-------------+------------+-------------------------------------------------+
| prod_id | vend_id | prod_name   | prod_price | prod_desc                                       |
+---------+---------+-------------+------------+-------------------------------------------------+
| anv21   |    1001 | 3 ton anvil | 19.99      | 333333hhhdhdh                                   |
| DTNTR   |    1003 | Detonator   | 13.00      | Detonator (plunger powered), fuses not included |
| FB      |    1003 | Bird seed   | 10.00      | Large bag (suitable for road runners)           |
+---------+---------+-------------+------------+-------------------------------------------------+
3 rows in set (0.09 sec)