Five retail sources, 1,070,374 records, 96 automated checks. Biggest defect: 47% of sales predate their product's launch, carrying 46% of $6.17B revenue.
Every row fixed, flagged, or quarantined under a versioned rules contract; never deleted. Revenue reconciled to $0.00 unexplained variance, verified by four independent engines (pandas x2, MySQL, Power Query).
Governed by a 23-entry decision log; least-privilege DB access.
I bring this rigor to client data: audit first, document every change, reconcile to zero.