日韩性视频-久久久蜜桃-www中文字幕-在线中文字幕av-亚洲欧美一区二区三区四区-撸久久-香蕉视频一区-久久无码精品丰满人妻-国产高潮av-激情福利社-日韩av网址大全-国产精品久久999-日本五十路在线-性欧美在线-久久99精品波多结衣一区-男女午夜免费视频-黑人极品ⅴideos精品欧美棵-人人妻人人澡人人爽精品欧美一区-日韩一区在线看-欧美a级在线免费观看

歡迎訪問 生活随笔!

生活随笔

當前位置: 首頁 > 运维知识 > 数据库 >内容正文

数据库

sql 基础--mysql 5

發(fā)布時間:2025/3/15 数据库 27 豆豆
生活随笔 收集整理的這篇文章主要介紹了 sql 基础--mysql 5 小編覺得挺不錯的,現(xiàn)在分享給大家,幫大家做個參考.

mysql5.6 安裝?http://jingyan.baidu.com/article/f3ad7d0ffc061a09c3345bf0.html

md中輸入:net start mysql,服務啟動成功

mysql -u root -p(第一次登錄沒有密碼,直接按回車過),登錄成功!

?

1.使用database

show databases;

use t_database;

show tables;

show columns from pw_luck;

mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | +--------------------+ 3 rows in set (0.00 sec)mysql> use mysql Database changed mysql> show tables; +---------------------------+ | Tables_in_mysql | +---------------------------+ | columns_priv | | db | | event | | func | | general_log | | help_category | | help_keyword | | help_relation | | help_topic | | innodb_index_stats | | innodb_table_stats | | ndb_binlog_index | | plugin | | proc | | procs_priv | | proxies_priv | | servers | | slave_master_info | | slave_relay_log_info | | slave_worker_info | | slow_log | | tables_priv | | time_zone | | time_zone_leap_second | | time_zone_name | | time_zone_transition | | time_zone_transition_type | | user | +---------------------------+ 28 rows in set (0.00 sec)

 2.查詢

 單列:select name from pw_luck;

 多列:select uid,name from pw_luck;

? ?所有:select * from pw_luck;

? ?distinct關(guān)鍵字(去重):select distinct name from pw_luck;

  注意:用在多個列上表示多個列值都一樣才會被去重

mysql> select * from pw_luck; +-----+-----------+------+ | uid | name | msg | +-----+-----------+------+ | 0 | Wilson | 100 | | 1 | zhangsan | 100 | | 2 | lisi | 1001 | | 3 | wang5 | 1001 | | 7 | zhangsan7 | 1000 | | 8 | zhangsan8 | 1000 | | 9 | zhangsan9 | 1000 | | 10 | wang5 | 1000 | +-----+-----------+------+ 8 rows in set (0.00 sec)mysql> select distinct name from pw_luck; +-----------+ | name | +-----------+ | Wilson | | zhangsan | | lisi | | wang5 | | zhangsan7 | | zhangsan8 | | zhangsan9 | +-----------+ 7 rows in set (0.00 sec)mysql> select distinct name,msg from pw_luck; +-----------+------+ | name | msg | +-----------+------+ | Wilson | 100 | | zhangsan | 100 | | lisi | 1001 | | wang5 | 1001 | | zhangsan7 | 1000 | | zhangsan8 | 1000 | | zhangsan9 | 1000 | | wang5 | 1000 | +-----------+------+ 8 rows in set (0.00 sec)

  想要得到多個列的結(jié)果且要對某一列去重 需要用到 group by 函數(shù)

mysql> select name,msg from pw_luck group by name; +-----------+------+ | name | msg | +-----------+------+ | lisi | 1001 | | wang5 | 1001 | | Wilson | 100 | | zhangsan | 100 | | zhangsan7 | 1000 | | zhangsan8 | 1000 | | zhangsan9 | 1000 | +-----------+------+ 7 rows in set (0.00 sec)

  限制結(jié)果:limit 2 表示 0-2行 limit 2,2 表示2行開始長度2行

如 select * from pw_luck limit 2,2

mysql> select * from pw_luck limit 2; +-----+----------+-----+ | uid | name | msg | +-----+----------+-----+ | 0 | Wilson | 100 | | 1 | zhangsan | 100 | +-----+----------+-----+ 2 rows in set (0.00 sec)mysql> select * from pw_luck limit 2,2; +-----+-------+------+ | uid | name | msg | +-----+-------+------+ | 2 | lisi | 1001 | | 3 | wang5 | 1001 | +-----+-------+------+ 2 rows in set (0.00 sec)

  3.排序?

  數(shù)據(jù)排序 ?select * from pw_luck order by name

  多行排序??select * from pw_luck order by name,msg

  升序,降序排列??select * from pw_luck order by name desc(降序)

          ?select * from pw_luck order by name asc(升序,默認不寫也可以),msg desc

  4.where 語句 過濾數(shù)據(jù)

mysql> select * from pw_luck where name='wang5'; +-----+-------+------+ | uid | name | msg | +-----+-------+------+ | 3 | wang5 | 1001 | | 10 | wang5 | 1000 | +-----+-------+------+ 2 rows in set (0.00 sec)

  不匹配檢查:<>

mysql> select * from pw_luck where msg <> 1000; +-----+----------+------+ | uid | name | msg | +-----+----------+------+ | 0 | Wilson | 100 | | 1 | zhangsan | 100 | | 2 | lisi | 1001 | | 3 | wang5 | 1001 | +-----+----------+------+ 4 rows in set (0.00 sec)

  between ... and... 范圍檢查

mysql> select * from pw_luck where msg between 1 and 1000; +-----+-----------+------+ | uid | name | msg | +-----+-----------+------+ | 0 | Wilson | 100 | | 1 | zhangsan | 100 | | 7 | zhangsan7 | 1000 | | 8 | zhangsan8 | 1000 | | 9 | zhangsan9 | 1000 | | 10 | wang5 | 1000 | +-----+-----------+------+ 6 rows in set (0.00 sec)

? ?null 空置檢查?

select * from pw_luck where name is not null;
select * from pw_luck where name is null; ? mysql> select * from pw_luck where name is not null; +-----+-----------+------+ | uid | name | msg | +-----+-----------+------+ | 0 | Wilson | 100 | | 1 | zhangsan | 100 | | 2 | lisi | 1001 | | 3 | wang5 | 1001 | | 7 | zhangsan7 | 1000 | | 8 | zhangsan8 | 1000 | | 9 | zhangsan9 | 1000 | | 10 | wang5 | 1000 | +-----+-----------+------+ 8 rows in set (0.00 sec)

? 5.組合語句:

  and ?or 操作符

  select * from pw_luck where name is not null and msg <2000;

  select * from pw_luck where name = 'wang5'or msg <1000;

  and 計算優(yōu)先級別高于 or 必要時候加上括號

mysql> select * from pw_luck where name = 'wang5'or msg <1000 and uid >3; +-----+-------+------+ | uid | name | msg | +-----+-------+------+ | 3 | wang5 | 1001 | | 10 | wang5 | 1000 | +-----+-------+------+ 2 rows in set (0.10 sec)mysql> select * from pw_luck where (name = 'wang5'or msg <1000 ) and uid >3; +-----+-------+------+ | uid | name | msg | +-----+-------+------+ | 10 | wang5 | 1000 | +-----+-------+------+ 1 row in set (0.01 sec)

  in 操作符

  select * from pw_luck where msg in (1000,1001);

  not 操作符:否定氣候的任何條件

mysql> select * from pw_luck where msg not in (1000,1001); +-----+----------+-----+ | uid | name | msg | +-----+----------+-----+ | 0 | Wilson | 100 | | 1 | zhangsan | 100 | +-----+----------+-----+ 2 rows in set (0.00 sec)

  6.通配符過濾 like

  %任何字符出現(xiàn)的次數(shù)(不匹配null)

  _任何單個字符

mysql> select * from pw_luck where name like 'wang%' or name like 'zhang%';
+-----+-----------+------+
| uid | name | msg |
+-----+-----------+------+
| 1 | zhangsan | 100 |
| 3 | wang5 | 1001 |
| 7 | zhangsan7 | 1000 |
| 8 | zhangsan8 | 1000 |
| 9 | zhangsan9 | 1000 |
| 10 | wang5 | 1000 |
| 11 | wang5% | 2000 |
+-----+-----------+------+
7 rows in set (0.00 sec)

? escape 查詢條件中包含通配符用 escape 過濾通配符

? 如下:M代表轉(zhuǎn)字符將后面的%轉(zhuǎn)義為普通% 等價于 搜索 包含wang5%的條件

mysql> select * from pw_luck where name like 'wang5M%' escape 'M'; +-----+--------+------+ | uid | name | msg | +-----+--------+------+ | 11 | wang5% | 2000 | +-----+--------+------+ 1 row in set (0.00 sec)

?

轉(zhuǎn)載于:https://www.cnblogs.com/wjw334/p/4283202.html

總結(jié)

以上是生活随笔為你收集整理的sql 基础--mysql 5的全部內(nèi)容,希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網(wǎng)站內(nèi)容還不錯,歡迎將生活随笔推薦給好友。