如何使用mysql选择组中的最后一条记录

Question

I am trying to select the LAST of the record in group by in sql. In my case I use this code

SELECT c_id
     , Max(transaction_num)
     , Max(trans_date) trans_date
     , doc_type
     , amount as balance
  from tbl_ledger 
 where doc_type = 'B' 
 group 
    by c_id

and the data of the selected column is this

so I basically trying to get the last balance amount. how can i select the last amount in sql?

the whole table content here : tbl_ledger

my output is getting the first balance amount:

Answer 1

The following query gives you the record that has the latest trans_date for each c_id :

select t.*
from tbl_ledger t
where 
    doc_type = 'B'
    and trans_date = (
        select max(t1.trans_date)
        from tbl_ledger t1
        where t1.doc_type = 'B' and t1.c_id = t.c_id
    )