我重新设计了一些代码,以将单个字段中的逗号分隔的字符串解析为单独的字段。我现在想合并循环以使用局部变量(我认为这是最好的方法)为新字段编号,以及在单例值[1]等中使用它们。
[[1]将是[WT1],[2]将是[SA1],[3] = [WT2],[4] = [SA2],依此类推
循环数需要由局部变量设置,并且会改变,所以我不能只制作有限数量的新字段用于输出。
我已经能够使用局部变量来替换NewXml.value字符串中的'Attribute',但是无法管理单例值的语法。
我想将变量i转换为字符串。我也想将其合并到循环中以输出新的字段名称,例如。 WT1,SA1,WT2,SA2等。
我已经注释掉了循环的代码行,以及我无法使用的SELECT中的第一个字段(WT1),它与现有WT1的行相同。
我希望我已经清楚地解释了自己,以寻求解决方案。
DECLARE @t TABLE(
ProductId INT,
ProductName VARCHAR(25),
SupplierId INT,
Descr VARCHAR(50)
)
INSERT INTO @t VALUES (1,'Product1',1,'A1,10in,30in,2lbs');
INSERT INTO @t VALUES (2,'Product2',2,'T6,15in,30in,');
INSERT INTO @t VALUES (3,'Product3',1,'A2,1in,,0.5lbs');
declare @i int;
set @i=1;
declare @prodatt VARCHAR(25);
set @prodatt ='Attribute';
--while @i < 8
--begin
SELECT
-- NewXML.value('(/Product[1]/Attribute[*[local-name() = sql:variable("@i")])]','varchar(25)') AS [WT1],
NewXML.value('(/Product[1]/*[local-name() = sql:variable("@prodatt")])[2]','varchar(25)') AS [SA1],
NewXML.value('/Product[1]/Attribute[1]','varchar(25)') AS [WT1],
-- NewXML.value('/Product[1]/Attribute[2]','varchar(25)') AS [SA1],
NewXML.value('/Product[1]/Attribute[3]','varchar(25)') AS [WT2],
NewXML.value('/Product[1]/Attribute[4]','varchar(25)') AS [SA2],
[ProductID],
[SupplierId]
FROM @t t1
CROSS APPLY (SELECT XMLEncoded=(SELECT Descr AS [*] FROM @t t2 WHERE t1.ProductId = t2.[ProductId] FOR XML PATH(''))) EncodeXML
CROSS APPLY (SELECT NewXML=CAST('<Product><Attribute>'+REPLACE(XMLEncoded,',','</Attribute><Attribute>')+'</Attribute></Product>' AS XML)) CastXML
这里是更清洁的实现。如果要使其绝对动态,则需要使用动态SQL。
SQL
-- DDL and sample data population, start
DECLARE @tbl TABLE (
ProductID INT PRIMARY KEY,
ProductName VARCHAR(25),
SupplierId INT,
Descr VARCHAR(50)
);
INSERT INTO @tbl VALUES
(1,'Product1',1,'A1,10in,30in,2lbs')
, (2,'Product2',2,'T6,15in,30in,')
, (3,'Product3',1,'A2,1in,,0.5lbs');
-- DDL and sample data population, end
DECLARE @separator CHAR(1) = ',';
-- Method #1, via XML
-- SQL Server 2008 onwards
;WITH rs AS
(
SELECT ProductID, Descr
, TRY_CAST(N'<root><r><![CDATA[' +
REPLACE(Descr, @separator, ']]></r><r><![CDATA[') +
']]></r></root>' AS XML) AS xmldata
FROM @tbl
)
SELECT ProductID, Descr
, xmldata.value('(/root/r[1]/text())[1]','VARCHAR(10)') AS WT1
, xmldata.value('(/root/r[2]/text())[1]','VARCHAR(10)') AS SA1
, xmldata.value('(/root/r[3]/text())[1]','VARCHAR(10)') AS WT2
, xmldata.value('(/root/r[4]/text())[1]','VARCHAR(10)') AS SA2
, xmldata.value('(/root/r[5]/text())[1]','VARCHAR(10)') AS WT3
, xmldata.value('(/root/r[6]/text())[1]','VARCHAR(10)') AS SA3
FROM rs;
输出
+-----------+-------------------+-----+------+------+--------+------+------+
| ProductID | Descr | WT1 | SA1 | WT2 | SA2 | WT3 | SA3 |
+-----------+-------------------+-----+------+------+--------+------+------+
| 1 | A1,10in,30in,2lbs | A1 | 10in | 30in | 2lbs | NULL | NULL |
| 2 | T6,15in,30in, | T6 | 15in | 30in | NULL | NULL | NULL |
| 3 | A2,1in,,0.5lbs | A2 | 1in | NULL | 0.5lbs | NULL | NULL |
+-----------+-------------------+-----+------+------+--------+------+------+