Query to lookup reference tables on sum the result - mysql

Question

I am new to SQL, would like to have your suggestions on how to solve this problem,
I have the sales information by type
I want to sum the Prices of certain references by Type and based on the resulting sum, fetch the values from another table and populate in the Output Column.
Group Type 100000 200000 300000
1 A 1 2 3
1 B 0 1 1
2 T 2 2 4
2 U 0 2 2
3 V 2 2 3
4 N 1 1 1
From the above table 2 we find the TYPE A and B belong to same group - Group 1. So in the first table, the query should sum Prices of the references belonging to the Group 1. If the sum is >100000 and <=200000 then based on the type the corresponding value must be chosen.
Incase the sum of Prices based on group is less than 100000 or the type not found in Table 2 then it should take the values from the below table
[+------+----+---+
| Type | 1 | 2 |
+------+----+---+
| A | 50 | 2 |
| B | 60 | 5 |
| C | 65 | 2 |
| D | 65 | 3 |
| E | 65 | 4 |
+------+----+---+][3]
Thus the final output for the above datasheet would be like below,
Order ID Reference Type Price Output
101 AAA A 500000 3
101 AAB B 100000 1
101 ABC C 20000 67
101 DCE B 50000 1
101 BOD D 200000 68
101 ZYZ E 200000 69
102 AAA A 20000 52
So for the first line, its TYPE A and Type A is present under Group 1 and in Group1 we also have Type 2. So for the same order ID 101 , the overall Sales of Type A and B is 650000 > 300000, therefore for Type A we chose the value 3 from the table 2. Since Type C is not present in Table 2, I went to Table 3 and added the two values and so on
Sorry for the long post. Hope my question is clear? Would like to have your expert opinion.
Thanks,
SS

Answer 1

Join all tables and make sure you do LEFT JOIN as we want to keep records from the first table even we don't have corresponding data in the second or third table.
For total count, give priority to the second table, use case when to verify in which range this mrp field is falling. If lies within a range pick count from the second table otherwise pick count from the third table.
SELECT
s.order_id,
s.reference,
s.`type`,
s.mrp,
#a:= IFNULL(g_total.Total, s.mrp) AS MRP_Total, -- #a variable to use it in CASE WHEN clause
CASE
WHEN #a > 100000 AND #a <= 200000 AND sg.`type` IS NOT NULL THEN sg.price_100000
WHEN #a > 200000 AND #a <= 300000 AND sg.`type` IS NOT NULL THEN sg.price_200000
WHEN #a > 300000 AND sg.`type` IS NOT NULL THEN sg.price_300000
ELSE tp.price_1 + tp.price_2
END Total
FROM sales s
LEFT JOIN sales_group sg ON s.`type` = sg.`type`
LEFT JOIN type_prices tp ON s.`type` = tp.`type`
LEFT JOIN (
SELECT
s.order_id, sgg.`group`, SUM(mrp) as Total
FROM sales s
INNER JOIN sales_group sgg ON s.`type` = sgg.`type`
GROUP BY s.order_id, sgg.`group`
) AS g_total -- Temp table to find total MRP, order and group wise
ON s.order_id = g_total.order_id AND sg.`group` = g_total.`group`
ORDER BY s.order_id, s.`type`;
Output:
sales
---
| order_id | reference | type | mrp | MRP_Total | Total |
---------------------------------------------------------
| 101 | AAA | A | 500000 | 650000 | 3 |
| 101 | DCE | B | 50000 | 650000 | 1 |
| 101 | AAB | B | 100000 | 650000 | 1 |
| 101 | ABC | C | 200000 | 200000 | 67 |
| 101 | BOD | D | 200000 | 200000 | 68 |
| 101 | ZYZ | E | 200000 | 200000 | 69 |
| 102 | AAA | A | 20000 | 20000 | 52 |
Note: sg.type IS NOT NULL is added in CASE WHEN clause because if we don't have any mapping in the second table, we should move to ELSE part which refers to the third table.