I wonder if checksum could be an alternative to a two-step process suggested by the article?

Something to the effect:

; WITH CTE

as (

SELECT worker_id,

CHECKSUM_AGG(CHECKSUM(rate_code)) as chk

FROM #worker_rate

GROUP BY worker_id

)

SELECT worker_id,

DENSE_RANK() OVER (ORDER BY chk) as SNO

FROM CTE