The following may be worth trying....
A spreadsheet called c:\JUNk\123.xls has a two worksheets 'march' and
'april' each with columns 'account', 'date' and 'value'
On a new worksheet in the same (or another) spreadsheet use >Data
Import External Data >New database Query, select 'Excel' files as the
data source. Find the spreadsheet called C:\JUNK\123.xls. Click on the
'SQL' button to display the sql code box. Enter the following....
SELECT `march$`.* FROM `C:\JUNK\123`.`march$` `march$`
union all
SELECT `april$`.* from `C:\JUNK\123`.`april$` `april$`
[may be easier to select the march worksheet into the query an click on
the " * " so all the correct file and worksheet addressing is set up for
you .. then edit the sql to the above format]
The data returned by the query will be all the rows in the March and
April worksheets combined into a single table that you can use as a
pivot table source.
For some reason unknown to me (using Excel 2003) a 'get external data'
can get the data from 2 other worksheets in the same open spreadsheet
but if you try to create a pivot table directly it will only let you do
it in another spreadsheet with the source spreadsheet closed.
regards