解析以逗号分隔的字符串，以使IN子句中的IN字符串列表

Question

我的存储过程接收一个以逗号分隔的字符串参数：

DECLARE @Account AS VARCHAR(200)
SET @Account = 'SA,A'

我需要从中做出这样的陈述：

WHERE Account IN ('SA', 'A')

这样做的最佳做法是什么？

Answer 1

创建此功能（sqlserver 2005 +）

CREATE function [dbo].[f_split]
(
@param nvarchar(max), 
@delimiter char(1)
)
returns @t table (val nvarchar(max), seq int)
as
begin
set @param += @delimiter

;with a as
(
select cast(1 as bigint) f, charindex(@delimiter, @param) t, 1 seq
union all
select t + 1, charindex(@delimiter, @param, t + 1), seq + 1
from a
where charindex(@delimiter, @param, t + 1) > 0
)
insert @t
select substring(@param, f, t - f), seq from a
option (maxrecursion 0)
return
end

使用此声明

SELECT *
FROM yourtable 
WHERE account in (SELECT val FROM dbo.f_split(@account, ','))

---

将我的拆分功能与XML拆分进行比较：

TESTDATA：

select top 100000 cast(a.number as varchar(10))+','+a.type +','+ cast(a.status as varchar(9))+','+cast(b.number as varchar(10))+','+b.type +','+ cast(b.status as varchar(9)) txt into a 
from master..spt_values a cross join master..spt_values b

XML：

 SELECT count(t.c.value('.', 'VARCHAR(20)'))
 FROM (
     SELECT top 100000 x = CAST('<t>' + 
           REPLACE(txt, ',', '</t><t>') + '</t>' AS XML)
           from a
 ) a
 CROSS APPLY x.nodes('/t') t(c)

Elapsed time: 1:21 seconds

f_split：

select count(*) from a cross apply clausens_base.dbo.f_split(a.txt, ',')

Elapsed time: 43 seconds

这将从一次运行变为另一次运行，但你明白了

Answer 2

试试这个 -

<强> DDL：

CREATE TABLE dbo.Table1 (
      [EmpId] INT
    , [FirstName] VARCHAR(7)
    , [LastName] VARCHAR(10)
    , [domain] VARCHAR(6)
    , [Vertical] VARCHAR(10)
    , [Account] VARCHAR(50)
    , [City] VARCHAR(50)
)

INSERT INTO dbo.Table1 ([EmpId], [FirstName], [LastName], [Vertical], [Account], [domain], [City])
VALUES 
     (345, 'Priya', 'Palanisamy', 'DotNet', 'LS', 'Abbott', 'Chennai'),
     (346, 'Kavitha', 'Amirtharaj', 'DotNet', 'CG', 'Diageo', 'Chennai'),
     (647, 'Kala', 'Haribabu', 'DotNet', 'DotNet', 'IMS', 'Chennai')

<强>查询：

DECLARE @Account VARCHAR(200)
SELECT @Account = 'CG,LS'

SELECT *
FROM Table1
WHERE [Vertical] = 'DotNet' AND (ISNULL(@Account, '') = '' OR Account IN (
     SELECT t.c.value('.', 'VARCHAR(20)')
     FROM (
         SELECT x = CAST('<t>' + 
               REPLACE(@Account, ',', '</t><t>') + '</t>' AS XML)
     ) a
     CROSS APPLY x.nodes('/t') t(c)
))

<强>输出：

扩展统计信息：

SSMS SET STATISTICS TIME + IO：

<强> XML：

(3720 row(s) affected)
Table 'temp'. Scan count 3, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

 SQL Server Execution Times:
   CPU time = 187 ms,  elapsed time = 242 ms.

<强> CTE：

(3720 row(s) affected)
Table '#BF78F425'. Scan count 360, logical reads 360, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'temp'. Scan count 1, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

 SQL Server Execution Times:
   CPU time = 281 ms,  elapsed time = 335 ms.

Answer 3

最有效的方法是使用CLR函数进行拆分字符串。有关示例和效果比较，请参阅this article