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數(shù)據(jù)庫基本操作語句有：

1 關(guān)于數(shù)據(jù)庫的基本操作

SHOW?DATABASES;??//查詢數(shù)據(jù)庫SHOW? CREATE?DATABASE?score;?//查詢數(shù)據(jù)庫的結(jié)構(gòu)CREATE? DATABASE?score?DEFAULT?CHARSET?utf8;?//創(chuàng)建數(shù)據(jù)庫 USE?score;??//使用score數(shù)據(jù)庫 DROP?DATABASE?score;??//刪除數(shù)據(jù)庫

2 關(guān)于表的操作

SHOW?TABLES;??????//顯示數(shù)據(jù)庫中的表CREATE?TABLE?score( sno?INT?PRIMARY?KEY?AUTO_INCREMENT, course?VARCHAR(20), sscore?SMALLINT);???//創(chuàng)建表SHOW?CREATE?TABLE?score;???//顯示構(gòu)造表語句DESC?score;　　?//顯示表結(jié) ALTER?TABLE?score ADD?startTime?DATE?NOT?NULL;???//添加字段ALTER?TABLE?score DROP?startTime;???//刪除字段ALTER?TABLE?score MODIFY?course?VARCHAR(50);???//修改字段類型ALTER?TABLE?score CHANGE?startTime?endTime?DATE;???//修改字段名DROP?TABLE?score;??//刪除表

3 管理數(shù)據(jù)

INSERT?INTO?score(course,sscore) VALUES('語文',80);???//添加數(shù)據(jù)UPDATE?score SET?sscore=90WHERE?sno=1;????//修改數(shù)據(jù)DELETE?FROM?score WHERE?sno=1;???//刪除數(shù)據(jù)

4 查詢數(shù)據(jù)

select?*?FROM?score;???//查詢所有字段數(shù)據(jù)

去重：select distinct 字段 from 表名 where 條件

邏輯條件： and or

比較條件：, >=, , between value1 and value2

判斷空：

　　1）判斷null: is null

　　2)判斷空字符串: =”” ? ?/ ?“”

模糊條件：like

　　%：替換任意長度字符

　　_:替換單個(gè)字符

分頁查詢，limit 起始行,查詢行數(shù)

排序：order by 字段 asc/desc

　　asc:升序

　　desc：降序

分組：group by 字段

5 數(shù)據(jù)庫中編碼查詢

SHOW?VARIABLES?LIKE?'character%';

Variable_name????Value character_set_client????utf8 character_set_connection????utf8 character_set_database????utf8 character_set_filesystem????binary character_set_results????utf8 character_set_server????utf8 character_set_system????utf8 character_sets_dir????C:Program?FilesMysqlMySQL?Server?5.7sharecharsets

如果在查詢過程中出現(xiàn)亂碼，可以通過設(shè)置相應(yīng)的字符編碼解決。

比如在cmd客戶端進(jìn)行查詢時(shí)，數(shù)據(jù)庫中可能有中文，數(shù)據(jù)庫character_set_client 設(shè)置的編碼是utf8，而cmd解釋是用gbk進(jìn)行解釋。所以會(huì)有亂碼，設(shè)置character_set_client 編碼為gbk即可。