php - Join two tables with group by condition

Here i want to join two table and want to produce the output like

Akbar Travels building      2018-10
Thrikandiyur Quarters       2018-10


Akbar Travels building     2018-11
Thrikandiyur Quarters      2018-11
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Here i have two tables nametable A,table B,table A structure looks like this

category_id              category_name  
    5               Akbar Travels building          
    6               Thrikandiyur Quarters 
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table B structure looks like this

id     paying_month     parent_category     
1         2018-10           5   
2         2018-10           5   
3         2018-11           5   
4         2018-11           5   
5         2018-10           6   
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Here for getting output i wrote my code code like this

public function get_date_wise_pdf_report($from, $to)
{
       $query=$this->db->query("SELECT * from tableA A left join tableB B  on A.category_id = B.parent_category and B.paying_month BETWEEN '{$from}' AND '{$to}' ");
       return $query->result();
 }
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but when i use this am getting like this

Akbar Travels building     2018-10
Akbar Travels building     2018-10
Akbar Travels building     2018-11
Akbar Travels building     2018-11
Thrikandiyur Quarters      2018-10
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Am unable to give group by statement here and if i gave only two rows will be the out come,please help me to solve