Microsoft U-SQL is the query language used on Azure Data Lake Analytics services. Based on SCOPE and Cosmos, which has been around since at least 2008, It combines C# type / expressions functionality, schema-on-read, custom processors and reducers into a SQL-like ETL and output language.
Keywords need to be upper case. The where clause uses C#-style == syntax. Rows can contain up to 4MB of data per row.
U-SQL supports SQL.MAP<k,v> and SQL.ARRAY(<T>)
U-SQL supports inline C# expressions, UDFs, UDAs to custom aggregate, UDOs to generate process and consume rowsets.
U-DOs are user-defined operators build with Visual Studio.
https://azure.microsoft.com/pt-pt/documentation/articles/data-lake-analytics-u-sql-develop-user-defined-operators/
It will be interesting to see if this language makes it into SQL Server itself. Extractors and Outputters would be highly useful to replace some of the functionality of SSIS.
I built a similar tool a few years ago for schema-on-read. It brought CSV files into BLOB columns in SQL Server (read my article on BLOBs on SQL Server Central) and allowed you to query them by converting to nvarchar(max), applying a schema, and then outputting to a table.
Kind of felt like a data lake at the time.... though it wasn't massively parallel and didn't have any kind of map-reduce job spinning up. Then MS introduced the filestream object...
