sql - SQL 将单词拆分为单独的字符

Question

我需要更改应用程序，我需要做的第一件事是更改数据库表中的字段。在此表中，我现在有 1 到 6 个单个字符，即 'abcdef' 我需要将其更改为 '[a][b][c][d][e][f]'

[编辑] 它意味着留在同一个领域。所以在 field = 'abcdef' 之前和 field = '[a][b][c][d][e][f]' 之后。

什么是这样做的好方法？

rg. 埃里克

Answer 1

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 2

您可以使用以下函数将字符串拆分为单独的字符：

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

然后将其应用为：

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 示例

Answer 3

不使用函数：

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