Yet another new M function for you this week: the Table.Schema() function, which returns information about the columns in a table. There’s some fairly detailed documentation about what it returns here ; a simple demo is always a lot more helpful though, I think. If you connect to the Adventure Works DW database in SQL Server and import the DimDate table, you’ll get an M query that returns the contents of that table (along with some extra columns that describe the relationships between that table and the others in the database): let Source = Sql.Database("localhost", "adventure works dw"), dbo_DimDate = Source{[Schema="dbo",Item="DimDate"]}[Data] in dbo_DimDate If you add an extra step to this query that calls the Table.Schema() function on the table returned by the dbo_DimDate step, like so: let Source = Sql.Database("localhost", "adventure works dw"), dbo_DimDate = Source{[Schema="dbo",Item="DimDate"]}[Data], GetSchema = Table.Schema(dbo_DimDate) in GetSchema …you get a table with one row for each column in the table returned by dbo_DimDate, and a lot of columns that give you information on each column such as its position in the table, its M data type, its data type in the original data source and so on: I can think of a lot of uses for this. Documenting a database is an obvious one; it would also serve as a much richer source of data when checking for changes in the structure of a data source, as I described here . Also, given how easy it is to tell whether two tables contain the same data in M , you could use this function to compare whether two tables have the same columns like so: let Source = Sql.Database("localhost", "adventure works dw"), dbo_DimDate = Source{[Schema="dbo",Item="DimDate"]}[Data], SomeOtherTable = Source{[Schema="dbo",Item="SomeOtherTable"]}[Data], TablesEquivalent = (Table.Schema(dbo_DimDate)=Table.Schema(SomeOtherTable )) in TablesEquivalent If you want more detail when doing comparisons you can do that with a little bit more M code , but that’s probably a topic for another post..
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