Linux Memo/MySQL文法のバックアップ(No.3)

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- 1 (2008-10-02 (木) 08:03:55)
- 2 (2008-10-02 (木) 08:18:56)
- 3 (2008-10-07 (火) 07:06:28)
- 4 (2008-10-13 (月) 07:21:45)
- 5 (2008-10-13 (月) 10:50:54)
- 6 (2008-10-13 (月) 11:11:29)
- 7 (2008-10-14 (火) 00:28:52)
- 8 (2008-11-13 (木) 13:03:09)
- 9 (2009-06-08 (月) 06:23:02)

MySQL文法 †

更新日2009-06-09 (火) 08:48:10

テーブル名の変更・複製 †

テーブル名の変更

ALTER TABLE 古いテーブル名 RENAME 新しいテーブル名;

mysql> ALTER TABLE ism_test RENAME ism_test2;
Query OK, 0 rows affected (0.00 sec)

テーブルの複製

create table 新しいテーブル名 as select * from 元のテーブル名;

mysql> create table ism_test as select * from ism_test2;
Query OK, 1 row affected (0.03 sec)
Records: 1  Duplicates: 0  Warnings: 0

必要なレコードだけ残しコピーすることも可

create table 新しいテーブル名 as select * from 元のテーブル名 where (条件);

↑

Select文いろいろ †

入れ子表現

入れ子は()で囲む

テーブルism_shouhinのすべてのIDフィールドの値と等しい、テーブルism_uriageのIDフィールドを抽出

mysql> select * from ism_uriage where ID in (select ID from ism_shouhin);
+----+---------------------------+------+-----------+-----------+------+
| ID | date                      | uid  | shouhinid | uriagesuu | etc  |
+----+---------------------------+------+-----------+-----------+------+
|  1 | 2008/09/27 (Sat) 23:41:05 | 3    |        14 |         2 | NULL |
|  2 | 2008/09/27 (Sat) 23:41:05 | 3    |        16 |         4 | NULL |
|  3 | 2008/09/27 (Sat) 23:41:05 | 3    |        18 |         6 | NULL |
|  5 | 2008/09/27 (Sat) 23:45:02 | 3    |        11 |         1 | NULL |

(略) 

| 33 | 2008/09/28 (Sun) 01:48:04 | 2    |        16 |         4 | NULL |
| 34 | 2008/09/28 (Sun) 01:50:02 | 2    |        20 |         2 | NULL |
| 35 | 2008/09/28 (Sun) 01:50:35 | 2    |        23 |         2 | NULL |
+----+---------------------------+------+-----------+-----------+------+
32 rows in set (0.01 sec)

フィールドの合計を別名で表示

mysql> select uid, uriagesuu, uid+uriagesuu as sum from ism_uriage where shouhinid=9;
+------+-----------+------+
| uid  | uriagesuu | sum  |
+------+-----------+------+
| 3    |         2 |    5 |
| 2    |         2 |    4 |
| 2    |         4 |    6 |

フィールドの文字の連結

mysql> select uid, uriagesuu, concat(uid, uriagesuu) as gousei from ism_uriage where shouhinid=9;
+------+-----------+--------+
| uid  | uriagesuu | gousei |
+------+-----------+--------+
| 3    |         2 | 32     |
| 2    |         2 | 22     |
| 2    |         4 | 24     |

数値比較して結果を表示

mysql> select uid, uriagesuu, strcmp(uid, uriagesuu) as hikaku from ism_uriage where shouhinid=9;
+------+-----------+--------+
| uid  | uriagesuu | hikaku |
+------+-----------+--------+
| 3    |         2 |      1 |
| 2    |         2 |      0 |
| 2    |         4 |     -1 |
| 2    |         4 |     -1 |
| 2    |         4 |     -1 |

select in

mysql> select * from ism_shouhin where ID in (10,12,15);
+------+---------------+------+--------+------+----------+------+
| ID   | name          | grp  | kakaku | url  | status   | etc  |
+------+---------------+------+--------+------+----------+------+
|   10 | ビール 500ml  | 201  |    360 |      |          |      |
|   12 | 発泡酒 500ml  | 201  |    164 |      |          |      |
|   15 | ワイン (ロゼ) | 201  |    680 |      | 販売終了 |      |
+------+---------------+------+--------+------+----------+------+
3 rows in set (0.00 sec)

否定形 [not in]

mysql> select * from ism_shouhin where ID not in (10,12,15);
+------+-------------------+------+--------+-----------------+------
| ID   | name              | grp  | kakaku | url | status    | etc  |
+------+-------------------+------+--------+-----+-----------+------
|    9 | ビール 350ml      | 201  |    250 |     |           |      |
|   11 | 発泡酒 350ml      | 201  |    134 |     |           |      |
|   13 | 焼酎 (芋)         | 201  |   1048 |     |           |      |
|   14 | 焼酎 (麦)         | 201  |   1148 |     |           |      |
|   16 | ワイン (白)       | 201  |    650 |     |           |      |
+------+-------------------+------+--------+-----+-----------+-------

↑

テーブル名の一時変更 †

mysql> select ID,name as 名前,kakaku as 単価 from ism_shouhin where ID in(10,12,15);
+------+---------------+------+
| ID   | 名前          | 単価 |
+------+---------------+------+
|   10 | ビール 500ml  |  360 |
|   12 | 発泡酒 500ml  |  164 |
|   15 | ワイン (ロゼ) |  680 |
+------+---------------+------+
3 rows in set (0.00 sec)

↑

テーブル結合 †

select ism_uriage.* , ism_shouhin.* from ism_uriage join ism_shouhin on  
ism_uriage.shouhinid=ism_shouhin.ID where ism_uriage.uid=2 order  by
ism_uriage.ID desc limit 3;
+-----+---------------------------+------+-----------+-----------+------+------+
----------------------------+------+--------+-----------------------------------
--------------------------------------------+--------+------+
| ID  | date                      | uid  | shouhinid | uriagesuu | etc  | ID    |
 name                       | grp  | kakaku | url    | status | etc  |
+-----+---------------------------+------+-----------+-----------+------+------+

----------------------------+------+--------+-----------------------------------
--------------------------------------------+--------+------+
| 160 | 2008/10/02 (Thu) 15:52:20 | 2    |         1 |         1 | NULL |    1 |
 冷蔵庫 AB-12345（H)        | 101  |  45000 |        |        |      |
| 159 | 2008/10/02 (Thu) 15:52:20 | 2    |        18 |         4 | NULL |   18 |
 カクテルバー(レモン)       | 201  |    121 |        |        |      |
| 158 | 2008/10/02 (Thu) 15:52:20 | 2    |        21 |         2 | NULL |   21 |
 コンパクトカメラ(Leica C2) | 301  |  37590 |        |        |      |
+-----+---------------------------+------+-----------+-----------+------+------+
----------------------------+------+--------+-----------------------------------
--------------------------------------------+--------+------+

3 rows in set (0.01 sec)

↑

テーブル作成・削除時のテーブル存在の確認 †

mysql> DROP TABLE IF EXISTS ism_test;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> create table if not exists ism_test( ID int8, date  varchar(64), etc  varchar(64));
Query OK, 0 rows affected (0.02 sec)

↑

フィールド名および型の変更 †

型の変更(data)

mysql> show fields from ism_test;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| ID    | bigint(20)  | YES  |     | NULL    |       |
| date  | varchar(64) | YES  |     | NULL    |       |
| etc   | varchar(64) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.01 sec)

mysql> alter table ism_test change date date int8;
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> show fields from ism_test;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| ID    | bigint(20)  | YES  |     | NULL    |       |
| date  | bigint(20)  | YES  |     | NULL    |       |
| etc   | varchar(64) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.01 sec)

名前の変更(data)

mysql> alter table ism_test change date data varchar(64);
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> show fields from ism_test;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| ID    | bigint(20)  | YES  |     | NULL    |       |
| data  | varchar(64) | YES  |     | NULL    |       |
| etc   | varchar(64) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

書式形式

alter table <テーブル名> change <フィールド名> <新フィールド名>　<型>

↑

入力されるデータの範囲越えのとき †

MySQLでは、定義さている値より多い値を入れようとすると、許容範囲まで入る。

dataが4Byte

mysql> show fields from ism_test;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| ID    | int(11)     | YES  |     | NULL    |       |
| data  | varchar(4)  | YES  |     | NULL    |       |
| etc   | varchar(64) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

dataに5byte入力してみると4Byteまで入る

mysql> insert into ism_test values(1,'12345','岡田');
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> select * from ism_test;
+------+------+------+
| ID   | data | etc  |
+------+------+------+
|    1 | 1234 | 岡田 |
+------+------+------+
1 row in set (0.00 sec)

フィールドの型を変更すると矛盾すると値がなくなる（varchar=>int型に変更した場合)

mysql> select * from ism_test;
+------+------+------+
| ID   | data | etc  |
+------+------+------+
|    1 | 1234 | 岡田 |
+------+------+------+
1 row in set (0.00 sec)

mysql> alter table ism_test change etc etc int4;
Query OK, 1 row affected, 1 warning (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 1

mysql> select * from ism_test;
+------+------+------+
| ID   | data | etc  |
+------+------+------+
|    1 | 1234 |    0 |
+------+------+------+
1 row in set (0.00 sec)

↑

フィールドの追加・削除 †

追加

mysql> show fields from ism_test;
+-------+------------+------+-----+---------+-------+
| Field | Type       | Null | Key | Default | Extra |
+-------+------------+------+-----+---------+-------+
| ID    | int(11)    | YES  |     | NULL    |       |
| data  | bigint(20) | YES  |     | NULL    |       |
| etc   | int(11)    | YES  |     | NULL    |       |
+-------+------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mysql> ALTER table ism_test add etc2 varchar(64);
Query OK, 1 row affected (0.01 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> show fields from ism_test;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| ID    | int(11)     | YES  |     | NULL    |       |
| data  | bigint(20)  | YES  |     | NULL    |       |
| etc   | int(11)     | YES  |     | NULL    |       |
| etc2  | varchar(64) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
4 rows in set (0.00 sec)

削除

mysql> ALTER table ism_test drop etc2;
Query OK, 1 row affected (0.01 sec)
Records: 1  Duplicates: 0  Warnings: 0

Linux Memo/MySQL文法 のバックアップ(No.3)