php select query to sum quantity of items sold order by date

php select query to sum quantity of items sold order by date

Need some help on this. Thanks in advance!
Here is my first table: table_bill
id table_id status added_date
73 1 1 9/1/2013 0:00
74 8 1 9/1/2013 0:00
75 17 1 9/1/2013 0:00
76 15 1 9/1/2013 0:00
77 20 1 9/1/2013 0:00
78 10 1 9/1/2013 0:00
79 4 1 9/1/2013 0:00
81 8 1 9/1/2013 0:00
82 16 1 9/1/2013 0:00
83 17 1 9/1/2013 0:00
84 14 1 9/1/2013 0:00
85 10 1 9/1/2013 0:00
86 9 1 9/1/2013 0:00
87 8 1 9/2/2013 0:00
88 11 1 9/2/2013 0:00
89 14 1 9/2/2013 0:00
90 2 1 9/2/2013 0:00
91 12 1 9/2/2013 0:00
92 30 1 9/2/2013 0:00
93 14 1 9/2/2013 0:00
94 5 1 9/2/2013 0:00
95 10 1 9/2/2013 0:00
96 2 1 9/2/2013 0:00
97 10 1 9/2/2013 0:00
98 11 1 9/3/2013 0:00
99 8 1 9/3/2013 0:00
100 11 1 9/3/2013 0:00
101 12 1 9/3/2013 0:00
102 20 1 9/3/2013 0:00
103 4 1 9/3/2013 0:00
And here is my second table: table_data
id bill_id item_id quantity
166 73 21 2
167 73 31 1
168 73 115 1
169 73 183 1
170 73 131 8
171 73 170 4
172 73 63 4
173 74 103 1
174 74 187 1
175 74 101 1
177 74 207 1
178 74 136 5
179 74 170 2
180 74 65 2
181 75 25 2
182 75 36 1
183 75 180 1
184 75 65 2
185 75 108 1
187 75 135 2
188 75 141 2
189 75 170 2
190 76 202 1
191 76 118 1
192 76 136 5
193 76 170 3
194 76 63 4
195 77 188 2
196 77 110 1
197 77 63 5
I want to get the sum of each item sold in a day datewise
Here is my query for the same....
$sql = "SELECT ocs.item_id, os.added_date, ocs.quantity FROM table_bill
os, table_data ocs WHERE os.id = ocs.bill_id";
However, i am getting sold item results multiple time for a day
For ex: if item number 1 is sold to 5 different customers in a day, i am
getting 5 different results for item number 1, i want the total number of
sale for that item number in a day.
Any help would be greatly appreciated. Thanks!