PostgreSQL: select ip range with max masklen

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with radius_cdr_pdp(sgsn_address, cdr_src_id) as (     values ('212.183.144.0'::inet, 1), ('212.183.144.0'::inet, 2), (null, 3) ), dt_ip_range(ip_range) as (     values ('212.183.144.0/16'::inet), ('212.183.144.0/24'::inet), ('212.182.0.0/16'::inet), (null) ), radius_cdr_pdp_max as (     select max(masklen(dt_ip_range.ip_range)) as max_masklen, cdr_src_id     from radius_cdr_pdp     left join dt_ip_range on radius_cdr_pdp.sgsn_address <<= dt_ip_range.ip_range     group by cdr_src_id ) select radius_cdr_pdp.sgsn_address, dt_ip_range.ip_range, radius_cdr_pdp.cdr_src_id, radius_cdr_pdp_max.max_masklen from radius_cdr_pdp join radius_cdr_pdp_max using (cdr_src_id) left join dt_ip_range     on radius_cdr_pdp.sgsn_address <<= dt_ip_range.ip_range     and radius_cdr_pdp_max.max_masklen = masklen(dt_ip_range.ip_range);