Array Formula Problem

[akovner]

I posted this earlier, but I explained it poorly, so here goes again.

I have a table (called 'Table1') which 2 columns. In column one is each month of 2010 (the first day of each month as a date), in column 2 is a 1 if the month has 31 days, 0 otherwise. In another table ('Table2') I have 10 months (the first day of each month as a date) and in the second column I have a revenue amount associated with that month. I wrote the following array formula:

=SUM(INDEX(Table1, MATCH(Table2[Column1], Table1[Column1], 0), 2) * Table2[Column2])

This should give me the sum of revenue for ONLY those months with 31 days, but instead I get the sum of revenue for ALL the months.

Strangely, when I enter just the piece inside the sum as an array formula (across 10 cells) I get the correct array. That is,

=INDEX(Table1, MATCH(Table2[Column1], Table1[Column1], 0), 2) * Table2[Column2]

Gives me an array with zeros for months with <31 days, and the proper revenue for months with 31 days.

Why isn't the 1-cell array formula working?

Thanks.

 

[AlphaFrog]

This is a SUMPRODUCT formula that only sums the Months with 31 days
<br /><table cellpadding="2.5px" rules="all" style=";background-color: #FFFFFF;border: 1px solid;border-collapse: collapse; border-color: #A6AAB6"><colgroup><col width="25px" style="background-color: #E0E0F0" /><col /><col /><col /><col /></colgroup><thead><tr style=" background-color: #E0E0F0;text-align: center;color: #161120"><th></th><th>A</th><th>B</th><th>C</th><th>D</th></tr></thead><tbody><tr ><td style="color: #161120;text-align: center;">1</td><td style="text-align: right;;">1/1/2011</td><td style="text-align: right;background-color: #FFFF99;;">1</td><td style="text-align: right;;"></td><td style=";">SUM of Months with 31 days</td></tr><tr ><td style="color: #161120;text-align: center;">2</td><td style="text-align: right;;">2/1/2011</td><td style="text-align: right;;">2</td><td style="text-align: right;;"></td><td style="text-align: center;;">152</td></tr><tr ><td style="color: #161120;text-align: center;">3</td><td style="text-align: right;;">3/1/2011</td><td style="text-align: right;background-color: #FFFF99;;">3</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">4</td><td style="text-align: right;;">4/1/2011</td><td style="text-align: right;;">4</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">5</td><td style="text-align: right;;">5/1/2011</td><td style="text-align: right;background-color: #FFFF99;;">5</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">6</td><td style="text-align: right;;">6/1/2011</td><td style="text-align: right;;">6</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">7</td><td style="text-align: right;;">7/1/2011</td><td style="text-align: right;background-color: #FFFF99;;">7</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">8</td><td style="text-align: right;;">8/1/2011</td><td style="text-align: right;background-color: #FFFF99;;">8</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">9</td><td style="text-align: right;;">9/1/2011</td><td style="text-align: right;;">9</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">10</td><td style="text-align: right;;">10/1/2011</td><td style="text-align: right;background-color: #FFFF99;;">10</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">11</td><td style="text-align: right;;">11/1/2011</td><td style="text-align: right;;">11</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">12</td><td style="text-align: right;;">12/1/2011</td><td style="text-align: right;background-color: #FFFF99;;">12</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">13</td><td style="text-align: right;;">1/1/2012</td><td style="text-align: right;background-color: #FFFF99;;">13</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">14</td><td style="text-align: right;;">2/1/2012</td><td style="text-align: right;;">14</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">15</td><td style="text-align: right;;">3/1/2012</td><td style="text-align: right;background-color: #FFFF99;;">15</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">16</td><td style="text-align: right;;">4/1/2012</td><td style="text-align: right;;">16</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">17</td><td style="text-align: right;;">5/1/2012</td><td style="text-align: right;background-color: #FFFF99;;">17</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">18</td><td style="text-align: right;;">6/1/2012</td><td style="text-align: right;;">18</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">19</td><td style="text-align: right;;">7/1/2012</td><td style="text-align: right;background-color: #FFFF99;;">19</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">20</td><td style="text-align: right;;">8/1/2012</td><td style="text-align: right;background-color: #FFFF99;;">20</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">21</td><td style="text-align: right;;">9/1/2012</td><td style="text-align: right;;">21</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">22</td><td style="text-align: right;;">10/1/2012</td><td style="text-align: right;background-color: #FFFF99;;">22</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">23</td><td style="text-align: right;;">11/1/2012</td><td style="text-align: right;;">23</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr></tbody></table><br /><br /><table cellpadding="2.5px" rules="all" style=";border: 2px solid black;border-collapse:collapse;padding: 0.4em;background-color: #FFFFFF" ><tr><td style="padding:6px" ><b>Worksheet Formulas</b><table cellpadding="2.5px" width="100%" rules="all" style="border: 1px solid;text-align:center;background-color: #FFFFFF;border-collapse: collapse; border-color: #A6AAB6"><thead><tr style=" background-color: #E0E0F0;color: #161120"><th width="10px">Cell</th><th style="text-align:left;padding-left:5px;">Formula</th></tr></thead><tbody><tr><th width="10px" style=" background-color: #E0E0F0;color: #161120">D2</th><td style="text-align:left">=SUMPRODUCT(<font color="Blue">--(<font color="Red">DAY(<font color="Green">A1:A23+30</font>)=31</font>),B1:B23</font>)</td></tr></tbody></table></td></tr></table><br />

 

[akovner]

Thank you for the swift response. To be honest, the case I presented is really a test case. What I really want to be able to do is use INDEX and MATCH in array formulas in general (I have a few problems which require this). I am really curious if there is a way to correct my formula while still using INDEX and MATCH, or some equivalent lookup functions.

Thanks again.