What problem does it solve? Writing Power Query M expressions for semantic model partitions is error-prone: syntax mistakes, broken query folding, and wrong column references often surface only during refresh. This Skill lets you author, validate, and test M expressions against real data sources before deploying them to a model. ## Core Features & Use Cases - M Expression Authoring: Write partition expressions with correct query folding order, early column pruning, row filtering, and explicit type handling. - Validation & Testing: Execute expressions via the Fabric executeQuery API against real data, or save to the model via XMLA/TOM for quick syntax checks. - Step-by-Step Debugging: Preview data at any step in the let...in chain by truncating the expression, with row limits via Table.FirstN. - Use Case: You need to add a filtered import partition for an Orders table. Generate the M expression, execute it against the SQL source to verify columns and types, then deploy it to the semantic model with confidence that folding is preserved. ## Quick Start Write and test a Power Query M expression for the Orders table partition in my semantic model, filtering out cancelled rows and previewing the first 100 rows.
