Joining multiple select sql statements (4 tables) - mysql

Question

I need to join together 2 SQL statements and both of those statements work on their own. But I don't know how to combine both into 1 SQL statement.
I have two tables in 1st statement, TR120 and TR1201.
The SQL is this:
select
PRODUCT, PRICE, QUANTITY, INVOICE.DATE
from
TR1201
left join
(select
DATE, ID as INVOICE_ID, INVOICE
from TR120) as INVOICE on INVOICE.INVOICE_ID = ID
where
INVOICE.DATE >= '2016-06-01' and INVOICE.DATE <= '2016-06-30'
This returns a list of all the products I sold, with price, quantity and date of sales in a specific time frame from 01-06-16 till 30-06-16.
Now I need to find out the latest price that I bought product for in different two tables TR100 and TR1001 based on the product and date of sale from the 1st SQL statement.
select
PRODUCT, PRICE, SUP.DATE
from
TR1001
left join
(select
DATE, ID as SUP_ID, SUP_INVOICE
from TR100) as SUP on SUP.SUP_ID = ID
This returns a list of all the products that I have bought with a price and a date. I only need last record from this query based on product and date of purchased.
TR120
ID | INVOICE | DATE
1 | 000001 |2016-06-05
2 | 000002 |2016-06-15
3 | 000003 |2016-06-25
TR1201
ID | PRODUCT | PRICE A | QUANTITY
1 | A | 2,00 | 5
2 | A | 2,00 | 2
3 | A | 2,00 | 1
TR100
ID | SUP_INVOICE | DATE
1 | 160001 | 2016-05-30
2 | 160002 | 2016-06-16
TR1001
ID | PRODUCT | PRICE B
1 | A | 0,5
2 | A | 0,7
The result I am trying to get is this:
PRODUCT | PRICE A (tr1201) | QUANTITY | DATE (tr100) | PRICE B (tr1001)
A | 2 | 5 | 2016-05-30 | 0,5
A | 2 | 2 | 2016-05-15 | 0,5
A | 2 | 1 | 2016-05-16 | 0,7
That is all I want to do :(

Answer 1

Have you tried first_value?
FIRST_VALUE ( [scalar_expression ] )
OVER ( [ partition_by_clause ] order_by_clause [ rows_range_clause ] )
it works like this:
select distinct id,
first_value(price) over (partition by id (,sup) order by date DESC (latest, ASC for oldest)) as last_price
from table;
Documentation can be found here: https://msdn.microsoft.com/en-us/library/hh213018.aspx

Answer 2

I don't have your tables so cannot test and therefore am providing advice only.
I think what you need is an Outer apply like this instead of joins
select
T1.Product
, T1.Price
, T2.DATE -- Alias this
, T2.Price -- Alias this
, T3.DATE -- Alias this
, T3.Price -- Alias this
from T1
OUTER APPLY (
select top 1
Date
,Price
from table2
WHERE ID = T1.Id AND product = T1.Product-- plus any other joins
ORDER BY Date desc
) as T2
OUTER APPLY (
select top 1
Date
,Price
from table3
WHERE ID = T1.Id AND product = T1.Product-- plus any other joins
ORDER BY Date desc
) as T3