MySQLの表の基本操作-2
14631 ワード
mysql> insert into teacher
-> values (202, 'robot', 'ZhuHai', '2013-04-24');
Query OK, 1 row affected (0.00 sec)
mysql> insert into teacher
-> values (203, 'Jack', 'ZhuHai', '2013-04-24');
Query OK, 1 row affected (0.00 sec)
mysql> insert into teacher
-> values (204, 'Ann', 'ZhuHai', '2013-04-24');
Query OK, 1 row affected (0.01 sec)
mysql> insert into teacher
-> values (205, 'Rose', 'ZhuHai', '2013-04-24');
Query OK, 1 row affected (0.01 sec)
(1)統計記録数
mysql> select count(*) from teacher;
+----------+
| count(*) |
+----------+
| 4 |
+----------+
row in set (0.01 sec)
mysql> select * from teacher;
+-----+-------+---------+------------+
| Id | name | address | year |
+-----+-------+---------+------------+
| 202 | robot | ZhuHai | 2013-04-24 |
| 203 | Jack | ZhuHai | 2013-04-24 |
| 204 | Ann | ZhuHai | 2013-04-24 |
| 205 | Rose | ZhuHai | 2013-04-24 |
+-----+-------+---------+------------+
rows in set (0.00 sec)
(2)投影操作、表示する情報の選択
mysql> select Id, year from teacher;
+-----+------------+
| Id | year |
+-----+------------+
| 202 | 2013-04-24 |
| 203 | 2013-04-24 |
| 204 | 2013-04-24 |
| 205 | 2013-04-24 |
+-----+------------+
rows in set (0.00 sec)
mysql> select Id, name from teacher;
+-----+-------+
| Id | name |
+-----+-------+
| 202 | robot |
| 203 | Jack |
| 204 | Ann |
| 205 | Rose |
+-----+-------+
rows in set (0.00 sec)
(3)プレビュー機能、フィールドの一部を表示する情報
mysql> select Id, left(address, 3) from teacher;
+-----+------------------+
| Id | left(address, 3) |
+-----+------------------+
| 202 | Zhu |
| 203 | Zhu |
| 204 | Zhu |
| 205 | Zhu |
+-----+------------------+
rows in set (0.00 sec)
mysql>