Question:  How to I compare dates in Oracle?

Answer: In Oracle, dates have a DATE internal format and comparing DATES should be with matching data types, preferably a DATE to DATE datatype.  If you avoid this data type mismatch and convert your text with the to_date function it is easy to compare dates in Oracle;

where my_date_col > to_date(2010-10-12,YYYY-MM-DD);

Below we compare to DATE in character format:

where to_char(my_char_col) > 2010-10-12

Comparing dates the wrong way

These Oracle date comparisons works, but no index cannot be used because date2 is invalidated with the trunc function (unless you create a function-based index on trunc(date2,'YYYY:MM').

where to_char(DATE1,'YYYY:MM') >= to_char(DATE2,'YYYY:MM')

where trunc(date1,'mm') >= trunc(date2,'mm');

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