使用SQL Server,我如何分割一个字符串,以便我可以访问项目x?
拿一根“你好,约翰·史密斯”的绳子。我如何通过空格分割字符串并访问索引1应该返回“约翰”的项目?
使用SQL Server,我如何分割一个字符串,以便我可以访问项目x?
拿一根“你好,约翰·史密斯”的绳子。我如何通过空格分割字符串并访问索引1应该返回“约翰”的项目?
当前回答
解析姓和名的简单解决方案
DECLARE @Name varchar(10) = 'John Smith'
-- Get First Name
SELECT SUBSTRING(@Name, 0, (SELECT CHARINDEX(' ', @Name)))
-- Get Last Name
SELECT SUBSTRING(@Name, (SELECT CHARINDEX(' ', @Name)) + 1, LEN(@Name))
在我的例子中(在许多其他人中似乎也是如此……),我有一个由一个空格隔开的姓和名列表。可以直接在选择语句中使用它来解析姓和名。
-- i.e. Get First and Last Name from a table of Full Names
SELECT SUBSTRING(FullName, 0, (SELECT CHARINDEX(' ', FullName))) as FirstName,
SUBSTRING(FullName, (SELECT CHARINDEX(' ', FullName)) + 1, LEN(FullName)) as LastName,
From FullNameTable
其他回答
Alter Function dbo.fn_Split
(
@Expression nvarchar(max),
@Delimiter nvarchar(20) = ',',
@Qualifier char(1) = Null
)
RETURNS @Results TABLE (id int IDENTITY(1,1), value nvarchar(max))
AS
BEGIN
/* USAGE
Select * From dbo.fn_Split('apple pear grape banana orange honeydew cantalope 3 2 1 4', ' ', Null)
Select * From dbo.fn_Split('1,abc,"Doe, John",4', ',', '"')
Select * From dbo.fn_Split('Hello 0,"&""&&&&', ',', '"')
*/
-- Declare Variables
DECLARE
@X xml,
@Temp nvarchar(max),
@Temp2 nvarchar(max),
@Start int,
@End int
-- HTML Encode @Expression
Select @Expression = (Select @Expression For XML Path(''))
-- Find all occurences of @Delimiter within @Qualifier and replace with |||***|||
While PATINDEX('%' + @Qualifier + '%', @Expression) > 0 AND Len(IsNull(@Qualifier, '')) > 0
BEGIN
Select
-- Starting character position of @Qualifier
@Start = PATINDEX('%' + @Qualifier + '%', @Expression),
-- @Expression starting at the @Start position
@Temp = SubString(@Expression, @Start + 1, LEN(@Expression)-@Start+1),
-- Next position of @Qualifier within @Expression
@End = PATINDEX('%' + @Qualifier + '%', @Temp) - 1,
-- The part of Expression found between the @Qualifiers
@Temp2 = Case When @End < 0 Then @Temp Else Left(@Temp, @End) End,
-- New @Expression
@Expression = REPLACE(@Expression,
@Qualifier + @Temp2 + Case When @End < 0 Then '' Else @Qualifier End,
Replace(@Temp2, @Delimiter, '|||***|||')
)
END
-- Replace all occurences of @Delimiter within @Expression with '</fn_Split><fn_Split>'
-- And convert it to XML so we can select from it
SET
@X = Cast('<fn_Split>' +
Replace(@Expression, @Delimiter, '</fn_Split><fn_Split>') +
'</fn_Split>' as xml)
-- Insert into our returnable table replacing '|||***|||' back to @Delimiter
INSERT @Results
SELECT
"Value" = LTRIM(RTrim(Replace(C.value('.', 'nvarchar(max)'), '|||***|||', @Delimiter)))
FROM
@X.nodes('fn_Split') as X(C)
-- Return our temp table
RETURN
END
试试这个:
CREATE function [SplitWordList]
(
@list varchar(8000)
)
returns @t table
(
Word varchar(50) not null,
Position int identity(1,1) not null
)
as begin
declare
@pos int,
@lpos int,
@item varchar(100),
@ignore varchar(100),
@dl int,
@a1 int,
@a2 int,
@z1 int,
@z2 int,
@n1 int,
@n2 int,
@c varchar(1),
@a smallint
select
@a1 = ascii('a'),
@a2 = ascii('A'),
@z1 = ascii('z'),
@z2 = ascii('Z'),
@n1 = ascii('0'),
@n2 = ascii('9')
set @ignore = '''"'
set @pos = 1
set @dl = datalength(@list)
set @lpos = 1
set @item = ''
while (@pos <= @dl) begin
set @c = substring(@list, @pos, 1)
if (@ignore not like '%' + @c + '%') begin
set @a = ascii(@c)
if ((@a >= @a1) and (@a <= @z1))
or ((@a >= @a2) and (@a <= @z2))
or ((@a >= @n1) and (@a <= @n2))
begin
set @item = @item + @c
end else if (@item > '') begin
insert into @t values (@item)
set @item = ''
end
end
set @pos = @pos + 1
end
if (@item > '') begin
insert into @t values (@item)
end
return
end
像这样测试它:
select * from SplitWordList('Hello John Smith')
Aaron Bertrand的回答很好,但也有缺陷。它不能准确地将空格作为分隔符处理(就像最初问题中的示例一样),因为长度函数将空格带在后面。
下面是他的代码,稍微调整了一下,允许使用空格分隔符:
CREATE FUNCTION [dbo].[SplitString]
(
@List NVARCHAR(MAX),
@Delim VARCHAR(255)
)
RETURNS TABLE
AS
RETURN ( SELECT [Value] FROM
(
SELECT
[Value] = LTRIM(RTRIM(SUBSTRING(@List, [Number],
CHARINDEX(@Delim, @List + @Delim, [Number]) - [Number])))
FROM (SELECT Number = ROW_NUMBER() OVER (ORDER BY name)
FROM sys.all_objects) AS x
WHERE Number <= LEN(@List)
AND SUBSTRING(@Delim + @List, [Number], LEN(@Delim+'x')-1) = @Delim
) AS y
);
declare @strng varchar(max)='hello john smith'
select (
substring(
@strng,
charindex(' ', @strng) + 1,
(
(charindex(' ', @strng, charindex(' ', @strng) + 1))
- charindex(' ',@strng)
)
))
好吧,我的代码并不那么简单,但下面是我用来将逗号分隔的输入变量分割为单个值,并将其放入表变量中的代码。我相信您可以稍微修改一下,根据空格进行分割,然后对该表变量执行基本的SELECT查询以获得结果。
-- Create temporary table to parse the list of accounting cycles.
DECLARE @tblAccountingCycles table
(
AccountingCycle varchar(10)
)
DECLARE @vchAccountingCycle varchar(10)
DECLARE @intPosition int
SET @vchAccountingCycleIDs = LTRIM(RTRIM(@vchAccountingCycleIDs)) + ','
SET @intPosition = CHARINDEX(',', @vchAccountingCycleIDs, 1)
IF REPLACE(@vchAccountingCycleIDs, ',', '') <> ''
BEGIN
WHILE @intPosition > 0
BEGIN
SET @vchAccountingCycle = LTRIM(RTRIM(LEFT(@vchAccountingCycleIDs, @intPosition - 1)))
IF @vchAccountingCycle <> ''
BEGIN
INSERT INTO @tblAccountingCycles (AccountingCycle) VALUES (@vchAccountingCycle)
END
SET @vchAccountingCycleIDs = RIGHT(@vchAccountingCycleIDs, LEN(@vchAccountingCycleIDs) - @intPosition)
SET @intPosition = CHARINDEX(',', @vchAccountingCycleIDs, 1)
END
END
概念是差不多的。另一种选择是利用SQL Server 2005本身的. net兼容性。实际上,您可以在. net中编写一个简单的方法,将字符串分割,然后将其作为存储过程/函数公开。