sql语句列转行

Posted 2023-04-13

参考技术A 主要应用case语句来解决行转列的问题
行转列问题主要分为两类
1)简单的行转列问题:
示例表:
id
sid
course
result
1
2005001
语文
80.0
2
2005001
数学
90.0
3
2005001
英语
80.0
4
2005002
语文
56.0
5
2005002
数学
69.0
6
2005002
英语
89.0
执行
select
sid,语文=isnull(sum(case
course
when
'语文'
then
result
end),0),
数学=isnull(sum(case
course
when
'数学'
then
result
end),0),
英语=isnull(sum(case
course
when
'英语'
then
result
end),0)
from
result
group
by
sid
order
by
sid
得出结果
sid
语文
数学
英语
2005001
80.0
90.0
80.0
2005002
56.0
69.0
89.0 参考技术B 这个不是用sql解决，而是用脚本语言解决！或者sql存数据的时候把c_003
c_004
c_005
变成字段，再录数据。转换也是用脚本语言！

sql 行转列 列转行

1、行转列一般通过case when语句来实现。

create table studentscores(
    username varchar(20),
    subject varchar(30),
    score float
);
insert into studentscores select ‘Nick‘,‘语文‘,80;
insert into studentscores select ‘Nick‘,‘数学‘,90;
insert into studentscores select ‘Nick‘,‘英语‘,70;
insert into studentscores select ‘Nick‘,‘生物‘,85;
insert into studentscores select ‘Kent‘,‘语文‘,80;
insert into studentscores select ‘Kent‘,‘数学‘,90;
insert into studentscores select ‘Kent‘,‘英语‘,70;
insert into studentscores select ‘Kent‘,‘生物‘,85;

select username,
 max(case subject when ‘语文‘ then score else 0 end) as ‘语文‘,
 max(case subject when ‘数学‘ then score else 0 end) as ‘数学‘,
 max(case subject when ‘英语‘ then score else 0 end) as ‘英语‘,
 max(case subject when ‘生物‘ then score else 0 end) as ‘生物‘
from studentscores
GROUP BY username;

 

create table inpours
(
    id int primary key AUTO_INCREMENT,
    username varchar(20),
    createtime datetime,
    paytype varchar(20),
    money decimal,
    issuccess bit
);

insert into inpours select 1,‘张三‘,‘2010-05-01‘,‘支付宝‘,50,1;
insert into inpours select 2,‘张三‘,‘2010-06-14‘,‘支付宝‘,50,1;
insert into inpours select 3,‘张三‘,‘2010-06-14‘,‘手机短信‘,100,1;
insert into inpours select 4,‘李四‘,‘2010-06-14‘,‘手机短信‘,100,1;
insert into inpours select 5,‘李四‘,‘2010-07-14‘,‘支付宝‘,100,1;
insert into inpours select 6,‘王五‘,‘2010-07-14‘,‘工商银行卡‘,100,1;
insert into inpours select 7,‘赵六‘,‘2010-07-14‘,‘建设银行卡‘,100,1;

select createtime,
 case paytype when ‘支付宝‘ then sum(money) else 0 end as ‘支付宝‘,
 case paytype when ‘手机短信‘ then sum(money) else 0 end as ‘手机短信‘,
 case paytype when ‘工商银行卡‘ then sum(money) else 0 end as ‘工商银行卡‘,
 case paytype when ‘建设银行卡‘ then sum(money) else 0 end as ‘建设银行卡‘
from inpours
group by createtime,paytype;

2、列转行，主要是通过UNION ALL，MAX来实现

create table progrectdetail(
    progrectname varchar(20),
    overseasupply int,
    nativesupply int,
    southsupply int,
    northsupply int
);

insert into progrectdetail select ‘A‘,100,200,50,50
union ALL
select ‘B‘,200,300,150,150
union ALL
select ‘C‘,159,400,20,320
union ALL
select ‘D‘,250,30,15,15;

select progrectname,‘OverseaSupply‘ as supplier,
max(overseasupply) as ‘supplynum‘
from progrectdetail
GROUP BY progrectname
union ALL
select progrectname,‘nativesupply‘ as supplier,
max(nativesupply) as ‘supplynum‘
from progrectdetail
GROUP BY progrectname
union ALL
select progrectname,‘southsupply‘ as supplier,
max(southsupply) as ‘supplynum‘
from progrectdetail
GROUP BY progrectname
union ALL
select progrectname,‘northsupply‘ as supplier,
max(northsupply) as ‘supplynum‘
from progrectdetail
GROUP BY progrectname;