sql / expert
Snippet
Multi-Column Comparison with Row Value Constructors
Row Value Constructors (Tuples) allow for comparing multiple columns as a single unit. This prevents the 'logic leak' where individual column matches (A or B) create false positives that a combined check (A and B) avoids.
snippet.sql
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SELECT *FROM inventory_movesWHERE (warehouse_id, shelf_id) IN (SELECT w_id, s_id FROM critical_zones);
Breakdown
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WHERE (warehouse_id, shelf_id)
Defines a row constructor consisting of two columns to be treated as a composite value.
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IN (SELECT w_id, s_id ...)
Checks for the existence of the composite pair within the result set of the subquery.