RedshiftでUUID v4生成

Redshift_uuid.sql

select
    id
    ,    replicate('0', 4 - len(w1)) || w1
      || replicate('0', 4 - len(w2)) || w2
      || '-'
      || replicate('0', 4 - len(w3)) || w3
      || '-'
      || replicate('0', 4 - len(w4)) || w4
      || '-'
      || replicate('0', 4 - len(w5)) || w5
      || '-'
      || replicate('0', 4 - len(w6)) || w6
      || replicate('0', 4 - len(w7)) || w7
      || replicate('0', 4 - len(w8)) || w8
      as visitor_uuid
from (
    select
        id
        , to_hex((random()*65535)::int) as w1
        , to_hex((random()*65535)::int) as w2
        , to_hex((random()*65535)::int) as w3
        , to_hex((random()*65535)::int & 4095 | 16384) as w4    -- & 0x0fff | 0x4000
        , to_hex((random()*65535)::int & 16383 | 32768) as w5   -- & 0x3fff | 0x8000
        , to_hex((random()*65535)::int) as w6
        , to_hex((random()*65535)::int) as w7
        , to_hex((random()*65535)::int) as w8
    from
        uuid_test
)
;