Selecting and comparing row pairs in oracle sql

select rownum, customer, mydate, mydata from
(select customer, mydate, mydata, row_number() over(partition by customer order by customer, date desc) myrn from table)
where myrn <=2;

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select CUST_NO "Customer number",
       NAME "Name",
       CIVIL_REG_CODE "Personal reg no",
       DISABILITY_PCT "DSP per centage",
       trunc(TIMESTAMP)
  from (select t.CUST_NO,n.NAME,n.Civil_Reg_Code,t.DISABILITY_PCT,t.TIMESTAMP, row_number() 
               over(partition by t.CUST_NO ORDER BY t.CUST_NO, t.TIMESTAMP DESC) myrn 
               from TIA.OBJ_IPGEN t, TIA.NAME n
               where myrn <= 2
               and n.ID_NO = t.CUST_NO
               and t.suc_seq_no IS NULL
               and t.DISABILITY_PCT <> 0)

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