Using Group By statement in Interbase

[SilverStray]

I have two similar tables, one seated on SQL Server, and the other in Interbase.
The lines of code that follow works perfectly well in SQL Server.

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select max(High) AS HIGH, min(Low) AS LOW, max(TotalVolume) as HiVol, min(TotalVolume)LowVol
from TB_Daily
where IssueID = 123 and year(TradedDte) = 1999
group by month(TradedDte)
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I made an equivalent SQL statement in Interbase as follows:

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select max(High) AS HIGH, min(Low) AS LOW, max(TotalVolume) as HiVol, min(TotalVolume)LowVol
from TB_Daily
where IssueID = 123 and extract(year from TradedDte) = 1999
group by extract(month from TradedDte)
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My problem is, I get an SQL error in the Group By portion using the Extract keyword. I am sure there's no problem in the syntax in extracting the month of the column TradedDte. The problem is in using it with the Group By statement. What should I do inorder to get the same results as delivered through my SQL statement used in SQL Server, where it performs the aggregate functions grouped by months???

Please help!!!

JEchavez