Query below count something we call Loner Tables and return it's statistics in database. This diagram illustrates the concept of loner tables:

Query

SELECT COUNT(*) AS Tables,
       SUM(CASE WHEN Rel.TableName IS NULL
                THEN 1 ELSE 0 END) AS LonerTables,
       100.00*SUM(CASE WHEN Rel.TableName IS NULL
                       THEN 1 ELSE 0 END)
            /COUNT(*) AS LonerRatio
FROM    DBC.TablesV Tab
LEFT JOIN   (
            SELECT DISTINCT ParentDb AS DatabaseName,
                   ParentTable AS TableName
            FROM All_RI_ParentsV
            UNION
            SELECT DISTINCT ChildDb,
                   ChildTable
            FROM All_RI_ChildrenV
) Rel   ON Rel.DatabaseName = Tab.DatabaseName
        AND Rel.TableName = Tab.TableName
WHERE   Tab.TableKind = 'T'
AND Tab.DatabaseName NOT IN ('All', 'Crashdumps', 'DBC', 'dbcmngr', 
    'Default', 'External_AP', 'EXTUSER', 'LockLogShredder', 'PUBLIC',
    'Sys_Calendar', 'SysAdmin', 'SYSBAR', 'SYSJDBC', 'SYSLIB', 
    'SystemFe', 'SYSUDTLIB', 'SYSUIF', 'TD_SERVER_DB', 'TDStats',
    'TD_SYSGPL', 'TD_SYSXML', 'TDMaps', 'TDPUSER', 'TDQCD',
    'tdwm', 'SQLJ', 'TD_SYSFNLIB', 'SYSSPATIAL');

Columns

• Tables - number of tables in database
• LonerTables - number of Loner Tables in the database
• LonerRatio - Loner Ratio - % of Loner Tables in the database

Rows

• Scope of rows: query returns one row

Sample results