MySql各種查詢

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1.簡單查詢

　　select * from info;

　　select Code as ‘代號‘,name as ‘姓名‘ from info;

2.條件查詢

　　select * from car where code = ‘c002‘;

　　select * from car where brand =‘b001‘ and power = 130; #或用or

3.模糊查詢

　　select * from car where name like ‘%奧迪%‘;  %代表任意多個字元包括0個 _代表一個字元

4.排序查詢

　　select * from car order by brand, powers desc; asc升序預設可以不寫

5。範圍查詢

　　select * from car where price between 40 and 60;

6.離散查詢

　　select * from car where code in(‘coo1‘,‘c003‘,‘c005‘,‘c007‘);

　　select * from car where code not in(‘coo1‘,‘c003‘,‘c005‘,‘c007‘);

7.統計查詢（彙總函式）

　　select count(code) from car;　　查詢資料條數也可以count(*)這麼寫，效能低

　　select sum(price) from car;　　求和

　　select max(code) from car;　　最大　　

　　select min(brand) from car;　　最小

　　select avg(price) from car;　　平均

8.分頁查詢

　　select * from Car limit (n-1)*5,5  #第n頁，每頁顯示五條資料

9.去重查詢

　　select distinct Brand from Car

10.分組查詢　

　　select brand,count(*),Brand from Car group by Brand 　　#把brand列的相同值組合起來，並這一條資料對該列或或其他列進行操作例如求平均值
　　select Brand from Car group by Brand having count(*)>3 #分組之後根據條件查詢使用having 不使用where

 

MySql各種查詢