SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE = 'BASE TABLE'
      AND TABLE_NAME NOT IN
            (SELECT OBJECT_NAME(id)
             FROM sysindexes
             WHERE indid = 1)

 

How to visualize the unused space for heap tables (with no clustered index)

/*
    Obtains spaced used data for ALL user tables in the database
*/
DECLARE @TableName VARCHAR(100)    --For storing values in the cursor

--Cursor to get the name of all user tables from the sysobjects listing
DECLARE tableCursor CURSOR
FOR
select [name]
from dbo.sysobjects
where  OBJECTPROPERTY(id, N'IsUserTable') = 1
FOR READ ONLY

--A procedure level temp table to store the results
CREATE TABLE #TempTable
(
    tableName varchar(100),
    numberofRows int,
    reservedSize varchar(50),
    dataSize varchar(50),
    indexSize varchar(50),
    unusedSize varchar(50)
)

--Open the cursor
OPEN tableCursor

--Get the first table name from the cursor
FETCH NEXT FROM tableCursor INTO @TableName

--Loop until the cursor was not able to fetch
WHILE (@@Fetch_Status >= 0)
BEGIN
    --Dump the results of the sp_spaceused query to the temp table
    INSERT  #TempTable
        EXEC sp_spaceused @TableName

    --Get the next table name
    FETCH NEXT FROM tableCursor INTO @TableName
END

--Get rid of the cursor
CLOSE tableCursor
DEALLOCATE tableCursor

--Select all records so we can use the reults
SELECT *
FROM #TempTable
ORDER BY numberofRows desc

--Final cleanup!
DROP TABLE #TempTable

GO