SQL 字符串拆分为单列

对 SQL 非常陌生，但我需要一些帮助，我确信这是一个简单的修复。

我在名为“Produce”的表中有一列数据，其中水果类型存储在名为“Fruit”的列中。此列中的某些值以逗号分隔。

有没有一种简单的方法来分割下面的内容，以便结果作为唯一条目的单列？

例如。示例表

Fruit
-----
Apple
Plum
Pear, Mango
Pear

我希望返回的是以下内容：

Fruit
-----
Apple
Plum
Pear
Mango

我尝试过使用字符串分割功能，但我想我已经完全掌握了。任何人都可以帮忙解释一下如何做到这一点吗？如果有帮助的话我正在使用 T-SQL。

提前致谢。

要解决的核心问题是停止将值存储为逗号分隔列表。保持数据标准化。话虽这么说...每个人都需要一个好的分离器...

declare @table table (Fruit varchar(64))
insert into @table
values
('Apple'),
('Plum'),
('Pear,Mango'),
('Pear')

select distinct
    Item
from
    @table
cross apply
    dbo.DelimitedSplit8K(Fruit,',')

或者，如果您使用的是 SQL Server 2016...

select distinct
    Item
from
    @table
cross apply
    string_split(Fruit,',')

功能

SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE FUNCTION [dbo].[DelimitedSplit8K] (@pString VARCHAR(8000), @pDelimiter CHAR(1))
--WARNING!!! DO NOT USE MAX DATA-TYPES HERE!  IT WILL KILL PERFORMANCE!

RETURNS TABLE WITH SCHEMABINDING AS
RETURN

/* "Inline" CTE Driven "Tally Table" produces values from 1 up to 10,000...
enough to cover VARCHAR(8000)*/

  WITH E1(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
                ),                          --10E+1 or 10 rows
       E2(N) AS (SELECT 1 FROM E1 a, E1 b), --10E+2 or 100 rows
       E4(N) AS (SELECT 1 FROM E2 a, E2 b), --10E+4 or 10,000 rows max
 cteTally(N) AS (--==== This provides the "base" CTE and limits the number of rows right up front
                     -- for both a performance gain and prevention of accidental "overruns"
                 SELECT TOP (ISNULL(DATALENGTH(@pString),0)) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
                ),
cteStart(N1) AS (--==== This returns N+1 (starting position of each "element" just once for each delimiter)
                 SELECT 1 UNION ALL
                 SELECT t.N+1 FROM cteTally t WHERE SUBSTRING(@pString,t.N,1) = @pDelimiter
                ),
cteLen(N1,L1) AS(--==== Return start and length (for use in substring)
                 SELECT s.N1,
                        ISNULL(NULLIF(CHARINDEX(@pDelimiter,@pString,s.N1),0)-s.N1,8000)
                   FROM cteStart s
                )
--===== Do the actual split. The ISNULL/NULLIF combo handles the length for the final element when no delimiter is found.
 SELECT ItemNumber = ROW_NUMBER() OVER(ORDER BY l.N1),
        Item       = SUBSTRING(@pString, l.N1, l.L1)
   FROM cteLen l
;
GO

Jeff Moden 的函数文章 http://www.sqlservercentral.com/articles/Tally+Table/72993/