Range of fields value output

[pr_blr]

I have events like

user name ,file location, city etc
city value is from 1-10 , what I want to make table that shows no of counts low 1-3, medium 4-6 and high 7-10 by user name , I tried to use case but not working properly and other solution please

[kml_uvce]

query

<your query> | rangemap field=city low=1-3 medium=4-6 high=7-10 | chart count(range) by username