Hi,

> Challenging sort problem for me. The rows can hold one to 
> four dates and output should be sorted by only one. date1 
> being primary and if that is missing date2 and so on. How can 
> this be efficiently done?  

Assuming the date elements are ordered,

  <xsl:sort select="(date1|date2|date3|date4)[1]"/>

Cheers,

Jarno