mysql表格查詢方法：

查詢：

1.簡單查詢

select * from Info --查所有數(shù)據(jù)

select Code,Name from Info --查指定列的數(shù)據(jù)

select Code as ‘代號(hào)‘,Name as ‘姓名‘ from Info --給列指定別名

2.條件查詢

select * from Info where Code=‘p001‘

select * from Info where Sex=‘true‘ and Nation=‘n001‘ --多條件并的關(guān)系

select * from Info where Sex=‘true‘ or Nation=‘n001‘ --多條件或的關(guān)系

3.范圍查詢

select * from Car where Price>40 and Price<50

select * from Car where Price between 40 and 50

4.離散查詢

select * from Car where Code in (‘c001‘,‘c005‘,‘c010‘,‘c015‘)

select * from Car where Code not in (‘c001‘,‘c005‘,‘c010‘,‘c015‘)

5.模糊查詢

select * from Car where Name like ‘%寶馬%‘ --查包含寶馬的

select * from Car where Name like ‘寶馬%‘ --查以寶馬開頭的

select * from Car where Name like ‘%寶馬‘ --查以寶馬結(jié)尾的

select * from Car where Name like ‘寶馬‘ --查等于寶馬的

select * from Car where Name like ‘__E%‘ --查第三個(gè)字符是E的

% 代表是任意多個(gè)字符

_ 代表是一個(gè)字符

6.排序查詢

select * from Car order by Price asc --以價(jià)格升序排列

select * from Car order by Price desc --以價(jià)格降序排列

select * from Car order by Oil desc,Price asc --以兩個(gè)字段排序，前面的是主條件后面的是次要條件

7.分頁查詢

select top 5 * from Car

select top 5 * from Car where Code not in (select top 5 Code from Car)

當(dāng)前頁:page = 2; 每頁顯示：row = 10;

select top row * from Car where Code not in (select top (page-1)*row Code from Car)

8.去重查詢

select distinct Brand from Car

9.分組查詢

select Brand from Car group by Brand having count(*)>2

10.聚合函數(shù)(統(tǒng)計(jì)查詢)

select count(*) from Car --查詢所有數(shù)據(jù)條數(shù)

select count(Code) from Car --查詢所有數(shù)據(jù)條數(shù)

select sum(Price) from Car --求和

select avg(Price) from Car --求平均

select max(Price) from Car --求最大值

select min(Price) from Car --求最小值

高級(jí)查詢

1.連接查詢

select * from Info,Nation --形成笛卡爾積

select * from Info,Nation where Info.Nation = Nation.Code

select Info.Code,Info.Name,Sex,Nation.Name,Birthday from Info,Nation where Info.Nation = Nation.Code

select * from Info join Nation on Info.Nation = Nation.Code --join on 的形式

2.聯(lián)合查詢

select Code,Name from Info

union

select Code,Name from Nation

3.子查詢

一條SQL語句中包含兩個(gè)查詢，其中一個(gè)是父查詢(外層查詢),另一個(gè)是子查詢(里層查詢),子查詢查詢的結(jié)果作為父查詢的條件。

--查詢民族為漢族的所有人員信息

select * from Info where Nation = (select Code from Nation where Name = ‘漢族‘)

(1)無關(guān)子查詢

子查詢可以單獨(dú)執(zhí)行，子查詢和父查詢沒有一定的關(guān)系

--查詢系列是寶馬5系的所有汽車信息

select * from Car where Brand =(select Brand_Code from Brand where Brand_Name = ‘寶馬5系‘)

(2)相關(guān)子查詢

--查找油耗低于該系列平均油耗的汽車

select * from Car where Oil

select avg(Oil) from Car where Brand = (該系列)

select * from Car a where Oil

MYSQL 查詢方法

標(biāo)簽：數(shù)據(jù)???ati???esc???相關(guān)子查詢???code???相關(guān)???笛卡爾積???卡爾???等于

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