with cat_claims as (select distinct claim_nbr from claims where cat = 1)

    select * from claims c
    inner join policies p on p.polnbr = c.polnbr
    inner join cat_claims cat on c.claim_nbr = cat.claim_nbr

with cat_claims as (select distinct claim_nbr from claims where cat = 1)

    select * into cat_claims
    from cat_claims

    select * from claims c
    inner join policies p on p.polnbr = c.polnbr
    inner join cat_claims cat on c.claim_nbr = cat.claim_nbr

    drop table cat_claims