I use vlookup (VLOOKUP(F3;$B$3:$C$7;2;FALSE) to search for each date in the second sheet to find a match in the first sheet, and return the corresponding values. That works fine. 

The problem is that in the first sheet, the same date can occur more than once, with different values, while the second sheet only searches for the dates once. That means only one value for the repeated dates will be counted.

Sheet (A) [table style="border-collapse: collapse; width: 103pt;" width="137" cellspacing="0" cellpadding="0" border="0"> [colgroup][col style="mso-width-source: userset; mso-width-alt: 2669; width: 55pt;" width="73">[/cOLIST] [col style="width: 48pt;" width="64">[/cOLIST] [/colgroup] [tbody] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt; width: 55pt;" width="73" align="right" class="xl63" height="20">2010-02-17[/td] [td style="width: 48pt;" width="64" align="right">2000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" class="xl63" height="20">2011-11-12[/td] [td align="right">1000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" class="xl63" height="20">2010-02-17[/td] [td align="right">5000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" class="xl63" height="20">2010-02-18[/td] [td align="right">300[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" class="xl63" height="20">2011-11-13[/td] [td align="right">600[/td] [/tr] [/tbody] [/table] Sheet (B) [table style="border-collapse: collapse; width: 107pt;" width="142" cellspacing="0" cellpadding="0" border="0"> [colgroup][col style="mso-width-source: userset; mso-width-alt: 2669; width: 55pt;" width="73">[/cOLIST] [col style="mso-width-source: userset; mso-width-alt: 2523; width: 52pt;" width="69">[/cOLIST] [/colgroup] [tbody] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt; width: 55pt;" width="73" align="right" class="xl65" height="20">2010-02-16[/td] [td style="width: 52pt;" width="69" align="right">0[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" class="xl65" height="20">2010-02-17[/td] [td align="right">2000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" class="xl65" height="20">2010-02-18[/td] [td align="right">300[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" class="xl65" height="20">2011-11-12[/td] [td align="right">1000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" class="xl65" height="20">2011-11-13[/td] [td align="right">600[/td] [/tr] [/tbody] [/table]

I have tried cross-searching, by first adding a column to the first spreadsheet, giving all dates a unique number: 1,2,3,4 and so on. After that, I have used vlookup on those numbers, getting all dates as result. That way I get the repeated dates as a search reference. However, when using these dates as startpoint for a second vlookup, all repeated dates get the value of the same date (see below, missing 5000).

Sheet (A)

[table style="border-collapse: collapse; width: 151pt;" width="201" cellspacing="0" cellpadding="0" border="0"> [colgroup][col style="width: 48pt;" width="64">[/cOLIST] [col style="mso-width-source: userset; mso-width-alt: 2669; width: 55pt;" width="73">[/cOLIST] [col style="width: 48pt;" width="64">[/cOLIST] [/colgroup] [tbody] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt; width: 48pt;" width="64" align="right" height="20">1[/td] [td style="width: 55pt;" width="73" align="right" class="xl65">2010-02-17[/td] [td style="width: 48pt;" width="64" align="right">2000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" height="20">2[/td] [td align="right" class="xl65">2011-11-12[/td] [td align="right">1000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" height="20">3[/td] [td align="right" class="xl65">2010-02-17[/td] [td align="right">5000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" height="20">4[/td] [td align="right" class="xl65">2010-02-18[/td] [td align="right">300[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" height="20">5[/td] [td align="right" class="xl65">2011-11-13[/td] [td align="right">600[/td] [/tr] [/tbody] [/table]

Sheet (B)

[table style="border-collapse: collapse; width: 151pt;" width="201" cellspacing="0" cellpadding="0" border="0"> [colgroup][col style="width: 48pt;" width="64">[/cOLIST] [col style="mso-width-source: userset; mso-width-alt: 2669; width: 55pt;" width="73">[/cOLIST] [col style="width: 48pt;" width="64">[/cOLIST] [/colgroup] [tbody] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt; width: 48pt;" width="64" align="right" height="20">1[/td] [td style="width: 55pt;" width="73" align="right" class="xl65">2010-02-17[/td] [td style="width: 48pt;" width="64" align="right">2000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" height="20">2[/td] [td align="right" class="xl65">2011-11-12[/td] [td align="right">1000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" height="20">3[/td] [td align="right" class="xl65">2010-02-17[/td] [td align="right">2000[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" height="20">4[/td] [td align="right" class="xl65">2010-02-18[/td] [td align="right">300[/td] [/tr] [tr style="height: 15.0pt;" height="20"> [td style="height: 15.0pt;" align="right" height="20">5[/td] [td align="right" class="xl65">2011-11-13[/td] [td align="right">600[/td] [/tr] [/tbody] [/table]

Is there a way to solve this?

Thanks in advance!