You can use OpenRefine to merge different variants of SEO keywords or urls and compute volume by cluster
1/ Choose the group you want to merge
Keywords column menu -> Edit cells -> Cluster and Edit -> Merge Selected & Re-Cluster
2/ Sort and reorder rows permanently
Keywords column menu -> Sort -> (text, A-Z)
Sort -> Reorder rows permanently
3/ Blank Down
Keywords column menu -> Edit cells -> Blank down
4/ Aggregate volume colum with same clusters and compute all totals
Search volume column menu -> Edit cells -> Join multivalued cells -> leave default (“,”)
Search volume column menu -> Edit cells -> Transform
Enter expression: forEach(value.split(‘,’),v,v.toNumber()).sum()
Congrats, you have merged different variants of SEO Keywords and sorted by trafic volume.