Not every table has a clustered index. Here is a quick script to find each table without a clustered index, also called a Heap, in your database.
Index Usage Stats Reset: Reading Them Without Being Fooled
Use index usage stats reset in SQL Server with practical examples, clear checks, and the limits you need before changing your database.
Moving a Table to Another Filegroup by Rebuilding Its Clustered Index
One statement moves the rows, but large-object data and other indexes stay behind. A small demo shows exactly where everything ends up.
Clustered Key Choice for Date Range Queries: Date or Identity
Should you cluster on OrderDate? Measure one month of orders on three designs and see what each one costs in reads before you rebuild a table.
Narrow Index Keys: Why the Clustered Key Width Matters Everywhere
Evaluate narrow index keys by comparing clustered GUID and integer designs, measuring index pages, and preserving natural uniqueness.
Count Rows and Indexes for Every Table in SQL Server
To count rows and indexes for every table, one query on the catalog views answers four questions at once: how many tables, which are heaps, how many nonclustered indexes each has, and how many rows each holds. The post tests it on a demo database and explains where the row count comes from.
Changing an Index In Place With CREATE INDEX and DROP_EXISTING
Use DROP_EXISTING to change an index definition in one operation, inspect its columns, and check online availability and dependencies.