MySql：如何选择所有值都相同的行？

Question

I have a table like this:

name |id | state
name1 12   4
name1 12   4
name2 33   3
name2 33   4
...

I want to select every name and id from table where state is only 4, that means name1 is correct, because it only has two records with state 4 and nothing more. Meanwhile name2 is wrong, because it has record with state 4 and record with state 3.

Answer 1

select name, id from mytable where id not in
(select distinct id from mytable where state <> 4)

Answer 2

You can use aggregation as shown below:

SELECT name, id
FROM your_table
GROUP BY name, id
HAVING SUM(state<>4)=0;

See a Demo on SQL Fiddle .

Answer 3

you might need 2 sub queries .

1. select with group by name were state 4
2. select with group by name

compare the count if the count is same then select it

example : select name , count (name) from table where state = 4 as T1 select name , count (name) from table as T2 select T1.name from T1 and T2 where T2.count = T1.count

Answer 4

You can use not exists like this:

select distinct name, id 
from table1 a
where not exists (select *
                  from table1 b
                  where  a.id=b.id and state<>4)

Answer 5

In a more general case you can use count distinct (with not exists or with a join):

select distinct name, id 
from table1 a
where not exists (
select *
from table1 b
where  a.id=b.id
group by id
HAVING count(distinct state)>1)