This query listed tables without primary keys and this one shows how many of them there are and what is the percentage of total tables.

Query

select 
    all_tabs.tables as all_tables,
    no_pk.tables as no_pk_tables,
    cast(100.0 * no_pk.tables / all_tabs.tables as decimal (14,2)) concat '%'
    as no_pk_percent
from
    (select count(*) as tables
    from 
    syscat.tables tab
    left outer join syscat.tabconst const 
        on const.tabschema = tab.tabschema 
        and const.tabname = tab.tabname and const.type ='P'
    where 
        tab.type ='T'
        and tab.tabschema not like 'SYS%'
        and const.constname is null
    ) as no_pk
inner join 
    (select count(*) as tables
    from syscat.tables 
    where type = 'T') as all_tabs
on 1 = 1

Columns

• all_tables - number of all tables in a database
• no_pk_tables - number of tables without a primary key
• no_pk_percent - percentage of tables without primary key in all tables

Rows

Query returns just one row.

Sample results

I checked how many tables in GSDB database do not have primary keys. It turns out it is only 4.62% which for me is a good result.