Derik Hammer has a script to estimate row counts in an Azure SQL Data Warehouse table:
Azure SQL Data Warehouse is a massively parallel processing (MPP) architecture designed for large-scale data warehouses. An MPP system creates logical / physical slices of the data. In SQL Data Warehouse’s case, the data has 60 logical slices, at all performance tiers. This means that a single table can have up to 60 different object_ids. This is why, in SQL Data Warehouse, there is the concept of physical and logical object_ids along with physical names.
Below is a query for finding row counts of tables in SQL Data Warehouse which accounts for the differences in architecture between my earlier script, written for SQL Server, and SQL Data Warehouse.
Click through for the script.