The array entered formula** proposed is:
Formula:
=IFERROR(INDEX(Data!A$2:A$9,SMALL(IF(Data!$E$2:$E$9=$L$1,(ROW(Data!$A$2:$A$9)-ROW(Data!$A$1))),ROWS($A$1:$A1))),"")
Note that the formula references cell L1 which is populated using a data validation in cell drop down.
The drop down references a list of months that is in column T and which may be moved and/or hidden for aesthetic purposes.
**Array formulas are not entered in the same way as 'standard' formulas. Instead of pressing just ENTER, you first hold down CTRL and SHIFT, and only then press ENTER. If you've done it correctly, you'll notice Excel puts curly brackets {} around the formula (though do not attempt to manually insert these yourself).
Let us know if you have any questions.
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