create database bankdb;
use bankdb;
##drop table user_info
create table user_info(
user_id int auto_increment primary key,
user_name nvarchar(30),
user_*** nvarchar(4)
);##drop table card_type
create table card_type(
usertype_id int auto_increment primary key,
usertype_name nvarchar(30)
);##drop table user_card
create table user_card(
usercard_id int auto_increment primary key,
usercard_number nvarchar(30),
usercard_pwd int,
usercard_remark text,
cardtype_id int,#外來鍵user_type
user_id int,#外來鍵user_info
foreign key(cardtype_id) references card_type(usertype_id) on delete cascade,##建立外來鍵關係語句
foreign key(user_id) references user_info(user_id) on delete cascade ##建立外來鍵關係語句
)type=innodb;
insert into user_card values (null,'500226198705088574',123456,'備註',1,1);
insert into user_card values (null,'500226199995088574',123456,'備註',2,1);
insert into user_card values (null,'500226155505088574',123456,'備註',3,1);
insert into user_card values (null,'500226198705088574',123456,'備註',1,2);
insert into user_card values (null,'500226777705088574',123456,'備註',1,3);
insert into user_card values (null,'500226192115088574',123456,'備註',1,4);
insert into user_card values (null,'500226097050488574',123456,'備註',1,6);
insert into user_card values (null,'500226777705088574',123456,'備註',2,3);
insert into user_card values (null,'500226192115088574',123456,'備註',3,4);
insert into user_card values (null,'500226097050488574',123456,'備註',1,8);
insert into user_info values (null,'張三0','男');
insert into user_info values (null,'張三1','女');
insert into user_info values (null,'張三2','男');
insert into user_info values (null,'張三3','男');
insert into user_info values (null,'張三4','男');
insert into user_info values (null,'張三5','男');
insert into user_info values (null,'張三6','女');
insert into user_info values (null,'張三7','女');
insert into card_type values (null,'信貸卡');
insert into card_type values (null,'借記卡');
insert into card_type values (null,'消費卡');
select * from user_info;
select * from card_type;
select * from user_card;
######查詢卡:信貸卡的使用者資訊記錄#######
##方法一：
select user_info.user_id,user_info.user_name,user_info.user_***
from user_info,user_card,card_type
where user_info.user_id=user_card.user_id
and user_card.cardtype_id=card_type.usertype_id
and card_type.usertype_name='信貸卡';
select * from user_info,user_card,card_type
##方法二
select * from user_info where user_id in(
select user_id from user_card where cardtype_id =(
select usertype_id from card_type where usertype_name='信貸卡')
);##左連線(以user_info為顯示基礎,user_card沒有符合條件則以null填充顯示)
select distinct * from user_info left join user_card on user_info.user_id=user_card.user_id
##右連線(與上面相反)
select distinct * from user_info right join user_card on user_info.user_id=user_card.user_id
##內連線(on等同於where)
select distinct * from user_info inner join user_card on user_info.user_id=user_card.user_id
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