SQL splitting a word in separate characters - sql

Question

I need to change an application and the first thing I need is to change a field in a database table.
In this table I now have 1 to 6 single characters, i.e. 'abcdef'
I need to change this to '[a][b][c][d][e][f]'
[edit] It is meant to stay in the same field. So before field = 'abcdef' and after field = '[a][b][c][d][e][f]'.
What would be a good way to do this?
rg.
Eric

Answer 1

You can split string to separate characters using following function:
create function ftStringCharacters
(
#str varchar(100)
)
returns table as
return
with v1(N) as (
select 1 union all select 1 union all select 1 union all select 1 union all select 1
union all
select 1 union all select 1 union all select 1 union all select 1 union all select 1
),
v2(N) as (select 1 from v1 a, v1 b),
v3(N) as (select top (isnull(datalength(#str), 0)) row_number() over (order by ##spid) from v2)
select N, substring(#str, N, 1) as C
from v3
GO
And then apply it as:
update t
set t.FieldName = p.FieldModified
from TableName t
cross apply (
select (select quotename(s.C)
from ftStringCharacters(t.FieldName) s
order by s.N
for xml path(''), type).value('text()[1]', 'varchar(20)')
) p(FieldModified)
SQLFiddle sample

Answer 2

DECLARE #text NVARCHAR(50)
SET #text = 'abcdef'
DECLARE #texttable TABLE (value NVARCHAR(1))
WHILE (len(#text) > 0)
BEGIN
INSERT INTO #texttable
SELECT substring(#text, 1, 1)
SET #text = stuff(#text, 1, 1, '')
END
select * from #texttable

Answer 3

Without using a function:
declare #t table(C varchar(18))
insert #t values('abc'), ('1234'), (' 1234a')
;with CTE as
(
select C, '[' + substring(c, a.n, 1) + ']' v, rn from
(select 1 n union all
select 2 union all
select 3 union all
select 4 union all
select 5 union all
select 6) a
cross apply
(select c, row_number() over (order by C) rn from #t group by c) b
where a.n <= len(C)
)
update t3
set C = t4.[value]
FROM #t t3
JOIN
(
select C,
(
select v
from CTE t1
where t1.rn = t2.rn
for xml path(''), type
).value('.', 'varchar(18)') [value]
from CTE t2
group by t2.rn, C
) t4
ON t3.C = t4.C
SELECT * FROM #t