是不是这样啊? Select count(distinct num2) from (select name,min(num2) as num2 from 表 group by name) aa或 Select count(distinct name) from (select num2,min(name) as name from 表 group by num2) aa
create table test3 ( cid varchar(3) , name1 varchar(5), num1 varchar(5), num2 varchar(5) ) insert into test3(cid,name1,num1,num2) values('1','e','11','222') insert into test3(cid,name1,num1,num2) values('2','a','21','333') insert into test3(cid,name1,num1,num2) values('3','b','22','333') insert into test3(cid,name1,num1,num2) values('4','c','23','444') insert into test3(cid,name1,num1,num2) values('5','c','23','555')select count(distinct num2) as 数目 from (select max(name1) as name1,max(num2) as num2 from test3 group by name1) test3
Select count(distinct num2)
from (select name,min(num2) as num2 from 表 group by name) aa或
Select count(distinct name)
from (select num2,min(name) as name from 表 group by num2) aa
钱怎么给你?
另外能指点下这个题目的解决思路么(或者帮忙解释一下这句语句)不然看不懂的话下次有类似的问题我自己还是不会
( cid varchar(3) ,
name1 varchar(5),
num1 varchar(5),
num2 varchar(5)
)
insert into test3(cid,name1,num1,num2) values('1','e','11','222')
insert into test3(cid,name1,num1,num2) values('2','a','21','333')
insert into test3(cid,name1,num1,num2) values('3','b','22','333')
insert into test3(cid,name1,num1,num2) values('4','c','23','444')
insert into test3(cid,name1,num1,num2) values('5','c','23','555')select count(distinct num2) as 数目 from (select max(name1) as name1,max(num2) as num2 from test3 group by name1) test3
drop test3