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Point-in-time lookup over SCD2 history

senior · sql🔒Walkthroughs

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Point-in-time lookup over SCD2 history

Using the dupes change log, answer a point-in-time question: what was each customer's email as of 2026-05-18?

Build the Type-2 versions (ignore NULL emails, collapse consecutive identical emails — same rules as the SCD2 build), then return the version that was in effect on 2026-05-18. A customer whose first email began *after* that date has no row.

Columns: customer_id, email_as_of. Sort by customer_id.

Tables & sample data

dupes

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query.sql

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