Copying Fields - Apache Solr Reference Guide - Apache Software Foundation

Both the source and the destination of copyField can contain asterisks, which will match anything. For example, the following line will copy the contents of all incoming fields that match the wildcard pattern *_t to the text field.:

?

<copyField source="*_t" dest="text" maxChars="25000" />

Icon

The copyField command can use a wildcard (*) character in the dest parameter only if the source parameter contains one as well. copyField uses the matching glob from the source field for the dest field name into which the source content is copied.

Read full article from Copying Fields - Apache Solr Reference Guide - Apache Software Foundation