问：怎么分页&&按条件&&按顺序&&姓名不重复查出数据？
答：其实就是行转列，那么，postgresql怎么进行转列呢，百度了下，大概有三种写法
写法1
group by + sum + case when
select name,
sum(case when zbfm='年龄' then value else end) as 年龄,
sum(case when zbfm='身高' then value else end) as 身高,
sum(case when zbfm='体重' then value else end) as 体重
from test group by name
having name like '%1' and length(name)= order by 年龄 desc
写法2
用postgresql的crosstab交叉函数
crosstab(unknown, unknown) does not exist
select * from
crosstab(
'select name,zbfm,value from test where name like ''%1'' and length(name)=4',$$values('年龄'), ('身高'), ('体重')$$)
as score(name text, 年龄 int, 身高 int, 体重 int)
order by 年龄 desc
写法3
group by + string_agg + split_part(分组，行转列，字符切割)
select name,
split_part(split_part(temp,',',),':',) as 年龄,
split_part(split_part(temp,',',),':',) as 身高,
split_part(split_part(temp,',',),':',) as 体重
from(
select name, string_agg(zbfm||':'||value,',') as temp from test
group by name
having name like '%1' and length(name)=
) as t order by 年龄 desc
group by + string_agg
select name, string_agg(zbfm||':'||value,',') from test
group by name
having name like '%1' and length(name)=
其他
建表语句
CREATE TABLE test
(
id serial NOT NULL,
value integer,
name character varying,
zbfm character varying,
CONSTRAINT pkey PRIMARY KEY (id)
)
插入数据(python)
import psycopg2
from random import random
conn = psycopg2.connect(database="postgres", user="postgres", password="password", host="ip", port="port")
cur = conn.cursor() def insertData():
names = ['路人甲', '王尼玛', '唐马儒']
zbfms = ['年龄', '身高', '体重'] for i in range(100):
sqlstr = 'insert into test(name, zbfm, value) values'
for j in range(100):
for name in names:
for zbfm in zbfms:
sqlstr += "('%s','%s',%d),"%(name+str(i*100+j),zbfm,int(100*random()))
cur.execute(sqlstr[:-1])
conn.commit()
print(i) if __name__ == '__main__':
insertData()
selectData()