Question: How to create unique distinct year and months from a long date listing (column A)?

You can find the question in this post: Extract dates using a drop down list in excel

Answer:

Array formula in C2:

=TEXT(INDEX($A$2:$A$135, MATCH(0, COUNTIF($C$1:C1, TEXT($A$2:$A$135, "mmm-yyyy")), 0)), "mmm-yyyy") + CTRL + SHIFT + ENTER

copied down as far as needed.

Download excel tutorial file

unique distinct year and month.xls
(Excel2007  Workbook *.xlsx)

Functions in this article:

INDEX(array,row_num,[column_num])
Returns a value or reference of the cell at the intersection of a particular row and column, in a given range

COUNTIF(range,criteria)
Counts the number of cells within a range that meet the given condition

MATCH(lookup_value;lookup_array; [match_type])
Returns the relative position of an item in an array that matches a specified value

TEXT(value, format_text)
Converts a value to text in a specific number format