我如何“计数” mysql中的列之前如何检索最后的id值？

Question

When i select the values of two tables

SELECT 
   tab.id
   ,tab.name
   ,tab2.id
   ,tab2.name
   ,count(distinct tab3.id) as totalusers
FROM master tab
  LEFT JOIN user as tab2 ON tab.id = tab2.cod
  LEFT JOIN user as tab3 ON tab.id = tab3.cod
WHERE tab.id = 5 limit 1
ORDER BY tab2.id DESC

OR

SELECT 
   tab.id
   ,tab.name
   ,tab2.id
   ,tab2.name
   ,count(tab2.id)
FROM master tab
  LEFT JOIN user as tab2 ON tab.id = tab2.cod
WHERE tab.id = 5 limit 1
ORDER BY tab2.id DESC

i got

+ ------ + -------- + ------- + --------- + ------------------ + 
| tab.id | tab.name | tab2.id | tab2.name | count(tab3.id)     |
+ ------ + -------- + ------- + --------- + ------------------ + 
| 5      | home1    | 132     | joao      | 3                  |
+ ------ + -------- + ------- + --------- + ------------------ + 

But the tab2.id retrieve the first value of table, the order doesn't works when i count the value, how do i get the last key 134 and his name ?

users

+ ---- + ----- + --- +
| id   | name  | cod |
+ ---- + ----- + --- +
| 132  | joao  |  5  |
+ ---- + ----- + --- +
| 133  | well  |  5  |
+ ---- + ----- + --- +
| 134  | cindy |  5  |
+ ---- + ----- + --- +

Obs.: the MAX() helps( Return last id and count of id ) but i need the name from users too, can i make it on where join without a subquery and with one line(limit 1) ?

Answer 1

seem you need inner join and group by

select tab.id, tab,name, t2.id, t2.name, count(*)
from tab
inner join 
(select id, name, code from 
user where id = (select max(id) from user )) t on t.cod = tab.code
inner join user as uset.code = tab.code
group by tab.id, tab,name, t2.id, t2.name