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MySQL文法 †更新日2009-06-09 (火) 08:48:10
アクセスlog情報 †logは/var/lib/mysqlのmysql-bin.xxxxにあるがバイナリなためツールを使用する # mysqlbinlog mysql-bin.000002 #080124 18:05:01 server id 2 end_log_pos 127 Query thread_id=11 exec_time=0 error_code=0 SET TIMESTAMP=1201165501; INSERT INTO `foo` VALUES (1,'Okada'),(2,'Okumura'),(3,'Yamada'); のようなログが見えいる mysqlbinlog: unknown variable 'default-character-set=utf8' のようなエラーが出たらmy.cnfの [client] ＃default-character-set = utf8 <=コメントアウトする ログファイルの種類
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 †重複キーを一度だけ取り出す方法 distinct key1のように指定するとkey1が重複しているときは1度だけ選択される このようにdistinctを指定する mysql> select distinct ktaiid from t_gps; レコードを指定して取得 はじめのレコードから3レコード取得 mysql> select * from ism_uriage limit 0,3; 3レコード目から4レコード取得 mysql> select * from ism_uriage limit 2,4; 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 varchar(X)のXについて †varchar(X) Xは255まで文字数を指定Byte数でない etcをvarchar(4)に指定し、同じ5byteで4文字と5文字で比較 mysql> show fields from t_test; +-------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+--------------+------+-----+---------+-------+ | No | text | NO | | | | | data | varchar(128) | NO | | | | | etc | varchar(4) | YES | | NULL | | +-------+--------------+------+-----+---------+-------+ 3 rows in set (0.00 sec) etcに'abあc'(5Byte,4文字)を入れると入る mysql> UPDATE t_test SET etc = 'abあc' WHERE No = 2; Query OK, 1 row affected (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> select * from t_test; +----+------------+--------+ | No | data | etc | +----+------------+--------+ | 1 | ABCD | あいう | | 2 | あいうえお | abあc | +----+------------+--------+ 2 rows in set (0.00 sec) etcに'abcde'(5Byte,5文字)を入れると入らない mysql> UPDATE t_test SET etc = 'abcde' WHERE No = 2; Query OK, 1 row affected, 1 warning (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 1 mysql> select * from t_test; +----+------------+--------+ | No | data | etc | +----+------------+--------+ | 1 | ABCD | あいう | | 2 | あいうえお | abcd | +----+------------+--------+ 2 rows in set (0.00 sec) |
