SQL Server 2017

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create table test(SequenceId varchar(20));
insert into test values
 ('2-10-14')
,('2-8-15')
,('2-8-16')
,('2-8-16')
,('2-17-21')
,('2-0-5')
,('4-1-10')
,('4-1-100')
;
select * from test


SequenceId


2-10-14

2-8-15

2-8-16

2-8-16

2-17-21

2-0-5

4-1-10

4-1-100


-- for SQL Server 
update test
set SequenceId= 
   concat(left(SequenceId,len(SequenceId)-charindex('-',reverse(SequenceId))+1)
    ,cast(cast(right(SequenceId,charindex('-',reverse(SequenceId))-1) as int)-1 as varchar)
  );
select * from test;



SequenceId


2-10-13

2-8-14

2-8-15

2-8-15

2-17-20

2-0-4

4-1-9

4-1-99


-- for SQL Server 2017
SELECT * 
  ,trim(translate(JSON_modify('[' + replace(SequenceId,'-',',') + ']','$[2]'
        ,JSON_value('[' + replace(SequenceId,'-',',') + ']','$[2]')-1)
      ,',[]','-  ')) NewSequenceId
FROM  test


SequenceId
NewSequenceId


2-10-13
2-10-12

2-8-14
2-8-13

2-8-15
2-8-14

2-8-15
2-8-14

2-17-20
2-17-19

2-0-4
2-0-3

4-1-9
4-1-8

4-1-99
4-1-98


-- for SQL Server 2016
SELECT * 
  ,replace(
    replace(
     replace(JSON_modify('[' + replace(SequenceId,'-',',') + ']','$[2]'
        ,JSON_value('[' + replace(SequenceId,'-',',') + ']','$[2]')-1)
      ,',','-') 
     ,'[','')
    ,']','')NewSequenceId
FROM  test



SequenceId
NewSequenceId


2-10-13
2-10-12

2-8-14
2-8-13

2-8-15
2-8-14

2-8-15
2-8-14

2-17-20
2-17-19

2-0-4
2-0-3

4-1-9
4-1-8

4-1-99
4-1-98

SequenceId	NewSequenceId
2-10-13	2-10-12
2-8-14	2-8-13
2-8-15	2-8-14
2-8-15	2-8-14
2-17-20	2-17-19
2-0-4	2-0-3
4-1-9	4-1-8
4-1-99	4-1-98