I have 2 tables: currencies and quotes
currencies
==========
id currency
-------------
quotes
======
id date id_currency value
-------------------------------
Index (date, id_currency - UNIQUE)
In order to find the most recent value for a currency I use the following
logic:
1. SELECT max(date), id_currency FROM quotes GROUP BY id_currency
2. for each set of values in result:
SELECT C.currency, Q.value FROM quotes Q, currencies C
WHERE C.id = Q.id_currency AND
Q.date = $result[max_date] AND
Q.id_currency = $result[id_currency]
The procedure is quite slow, because for the 2nd step I have nnn queries
where nnn = number of rows in the 1st step.
Could you suggest a better and faster approach ?
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