PDO & MySQL: Subquery using dynamic time? Way to solve using Join by avoiding while loop?

Question

In trying to pull down some stock data after a certain set of criteria is triggered from a database I am getting a slow response mostly based around using dynamic data. I have

Answer 1

Just quickly, you seem to have one too many "OR"

WHERE   
    (
    y.exchange = 'NASDAQ CM' OR
    y.exchange = 'NASDAQ GM' OR
    )
    AND k.t BETWEEN 20150101 AND 20150110

Should be ...

WHERE   
    (
    y.exchange = 'NASDAQ CM' OR
    y.exchange = 'NASDAQ GM'
    )
    AND k.t BETWEEN 20150101 AND 20150110