mysql - mySQL 从多个表中选择列而不重复数据

Question

create table Student (
St_ID int not null,
St_Name varchar (100),
St_tel int,
St_ADD varchar (100) not null,
St_city varchar (100)not null,
St_type varchar (20) not null,
St_nationality varchar (20) not null,
Dep_ID int,
C_ID int,
primary key (St_ID),
foreign key (Dep_ID) references Department(Dep_ID),
foreign key (C_ID) references Course(C_ID),

)

create table Course (
C_ID int not null,
C_Name varchar (30) not null,
C_Duration varchar (10) not null,
DegreeType varchar (20),
Dep_ID int,
primary key (C_ID),
foreign key (Dep_ID) references Department (Dep_ID),
)


insert into Course Values (4040,'Software Engineering','18months','HND',001)
insert into Course Values (1454,'Business IT','6months','Diploma',001)
insert into Course Values (1534,'Business management ','18months','HND',002)
insert into Course Values (1245,'Digital Media','6months','Diploma',001)
insert into Course Values (1243,'Business Development','10months','Diploma',001)

INSERT INTO Student VALUES (1212,'jerome jacobs',0774750407,'no 66/7 senananyake lane ','nawala','fulltime','HND','SL',001,4040);

INSERT INTO Student VALUES (1713,'john paul',0773435646,'no 77/9 alvatigala  lane','colombo ','parttime','Diploma','SL',001,1454);

INSERT INTO Student VALUES (1614,'Angelo mathews',0773436777,'no 88 rose lane colombo ','colombo 2','fulltime','HND','SL',002,1534);

INSERT INTO Student VALUES (1514,'jean paul',0713556688,'no 100/1 4th lane nawala','nawala','fulltime','Diploma','SL',002,1245);

INSERT INTO Student VALUES (1316,'Mark francis',0755657665,'no 54 1st lane ','kotte','parttime','HND','SL',003,4040);

INSERT INTO Student VALUES (1117,'Kevin steffan',0757667687,'no 99/5 railway lane ','nugegoda','parttime','Diploma','SL',004,1243);

SELECT DISTINCT  Student.St_ID,St_Name,St_tel,St_ADD,St_type,DegreeType,C_Name  from Student,Course where Student.St_type='parttime' and Course.DegreeType='HND';

这是我从两个表中获取信息的查询，但它重复值我该如何解决这个问题，我对 sql 非常好奇，我是一个初学者，对我提出问题的方式感到抱歉，如果得到解答，我将非常满意

Answer 1

您必须使用公共(public)字段JOIN表:

SELECT DISTINCT Student.St_ID,St_Name,St_tel,St_ADD,St_type,DegreeType,C_Name  
from Student JOIN 
     Course ON Student.C_ID =Course.C_ID 
where Student.St_type='parttime' and Course.DegreeType='HND';

SQL JOIN 子句用于根据两个或多个表之间的公共(public)字段组合来自两个或多个表的行。

了解有关联接的更多信息 here .