Adding a, b, c to end of data [closed] - tsql

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Closed 10 years ago.
I have table with contract_code column, but in this column have same data, how can I change the same data to samedata_a, and samedata_b and etc.
For example:
Change this data
ASFRETERT
JDFJDSFJS
ASFRETERT
TO
ASFRETERT_a
JDFJDSFJS
ASFRETERT_b

Answer 1

You can perform this by applying a row_number() to the column. If you don't need the additional character to be an alpha character then it would be easier using the following:
The first version using CTE:
-- cte version
;with cte as
(
select col1, row_number() over(partition by col1 order by col1) rn
from yourtable
)
select
case when t1.cnt > 1
then c.col1 + '_'
+ cast(c.rn as varchar(10))
else c.col1
end yourColumn
from cte c
inner join
(
select count(*) cnt, col1
from yourtable
group by col1
) t1
on c.col1 = t1.col1;
The second version uses sub-queries
-- non-cte version
select case when t2.cnt > 1
then t1.col1 + '_'
+ cast(t1.rn as varchar(10))
else t1.col1
end yourColumn
from
(
select col1, row_number() over(partition by col1 order by col1) rn
from yourtable
) t1
inner join
(
select count(*) cnt, col1
from yourtable
group by col1
) t2
on t1.col1 = t2.col1
See SQL Fiddle with Demo. The two versions above add an integer to the end of the column but if you want to apply an alpha character, you should add a function to your database (Code for function from this question on StackOverflow):
CREATE FUNCTION dbo.fnColumnNameFromIndex(#i int)
RETURNS varchar(3)
AS
BEGIN
DECLARE #dividend int, #letters varchar(3), #modulo int
SET #dividend = #i
SET #letters = ''
WHILE #dividend > 0
BEGIN
SET #modulo = (#dividend - 1) % 26
SET #letters = CHAR(65 + #modulo) + #letters
SET #dividend = CONVERT(int, (#dividend - #modulo) / 26 )
END
RETURN #letters
END
If you create this function, then you can get the alpha character for each row. Your queries would then be:
The CTE version:
-- cte version
;with cte as
(
select col1, row_number() over(partition by col1 order by col1) rn
from yourtable
)
select
case when t1.cnt > 1
then c.col1 + '_'
+ cast(dbo.fnColumnNameFromIndex(c.rn) as varchar(10))
else c.col1
end yourColumn
from cte c
inner join
(
select count(*) cnt, col1
from yourtable
group by col1
) t1
on c.col1 = t1.col1;
The sub query version:
-- non-cte version
select case when t2.cnt > 1
then t1.col1 + '_'
+ cast(dbo.fnColumnNameFromIndex(t1.rn) as varchar(10))
else t1.col1
end yourColumn
from
(
select col1, row_number() over(partition by col1 order by col1) rn
from yourtable
) t1
inner join
(
select count(*) cnt, col1
from yourtable
group by col1
) t2
on t1.col1 = t2.col1
See SQL Fiddle with Demo