1.普通查詢
select * from info; #查詢所有內容
select Code,Name from Info #查詢某幾列
2.條件查詢
select * from Info where Code='p001' #條件查詢
select * from Info where Nation ='n001' and Sex= true #條件之間並的關系
select * from Info where Nation = 'n001' and sex = '1'
select * from Info where Sex = false or Nation = 'n002'#條件之間或者的關系
3.模糊查詢（搜索關鍵字）
select * from Chinastates where areaname like '中%' #查詢以中開頭的
select * from Chinastates where Areaname like '%城%' #查詢包含 城的信息
select * from Chinastates where Areaname like '_城%' #查詢城 在第二個位置出現的數據
4.排序
select * from Car order by Code desc #desc降序 asc升序
select * from Car order by Brand
select * from Car order by Brand,Powers #按照兩個列排序
5.統計查詢（聚合函數）
select count(*) from Car #查詢總條數 * 代表所有列
select count(Code) from Car #查詢某一列
select max(Price) from Car #查詢 price列裡的最大值
select min(price) from Car #查詢最小值
select avg(price) from Car #查詢平均值
select sum(price) from Car #查詢總和
6.分組查詢
select Brand,count(*) from Car group by Brand #根據系列(Brand)分組(group)查看每組的數據條數
select Code,Brand,count(*) from Car group by Brand #根據Brand分組查看Code，Brand的數據條
select * from Car group by Brand having count(*) >2 #查詢分組之後數據條數大於2的,group後面不能加 where
7.分頁查詢
select * from Car limit 0,5 #查詢跳過0條 取5條
select * from Car limit 5,5 #跳過幾條取幾條數據
