Tente isso
SELECT T.*,S.* FROM
(
Select TD.category_name,TD.branch_name,TM.created_date,TM.user_id,TD.order_details_id,TD.branch_id
From tbl_orderdetails TD Inner Join tbl_ordermaster TM ON
TD.order_master_id = TM.ordermasterid
Where TM.user_id='12'
) T Left Join
(
Select T1.branch_name,Count(T1.branch_name) As No_Of_Branch
From tbl_orderdetails T1 Inner Join tbl_ordermaster T2 ON
T1.order_master_id = T2.ordermasterid
Where T2.user_id='12'
Group By T1.branch_name
) S On S.branch_name = T.branch_name
Atualizar
Se você deseja obter
Max
de count
Tente isso
SELECT T.*,S.* FROM
(
Select TD.category_name,TD.branch_name,TM.created_date,TM.user_id,TD.order_details_id,TD.branch_id
From tbl_orderdetails TD Inner Join tbl_ordermaster TM ON
TD.order_master_id = TM.ordermasterid
Where TM.user_id='12'
) T Inner Join
(
SELECT M.branch_name,Max(M.No_Of_Branch) FROM
(
Select T1.branch_name,Count(T1.branch_name) As No_Of_Branch
From tbl_orderdetails T1 Inner Join tbl_ordermaster T2 ON
T1.order_master_id = T2.ordermasterid
Where T2.user_id='12'
Group By T1.branch_name
) M Group By M.branch_name
) S On S.branch_name = T.branch_name