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create table your_table (SDO int,Startmonth varchar(3),endmonth varchar(3), rate int);
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insert into your_table values (101,'jan','mar',10), (101,'feb','mar',20), (101,'may','jul',30);
3 rows affected
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Select * from ( select case when tab2.SDO is null then tab1.SDO else tab2.SDO end as SDO, case when tab2.Startmonth is null then tab1.Startmonth else tab2.Startmonth end as Startmonth, case when tab2.endmonth is null then tab1.endmonth else tab2.endmonth end as endmonth, case when tab2.rate is null then tab1.rate else tab2.rate end as rate from your_table tab1 left join your_table tab2 on (tab2.Startmonth > tab1.Startmonth and tab2.Startmonth < tab1.endmonth ) or tab2.Startmonth is null ) as tab group by SDO,Startmonth,endmonth,rate having count(*) = 1
SDO Startmonth endmonth rate
101 may jul 30
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