这是一个完全有效的示例。
您告诉我们,性能很重要,所以不要使用标量 UDF!
像这样尝试一下(下次你的工作就是创建一个 (减少了!!!) MCVE https://stackoverflow.com/help/mcve:
CREATE DATABASE testDB;
GO
USE testDB;
GO
CREATE TABLE Booking(BookingID INT CONSTRAINT PK_Booking PRIMARY KEY
,SomeBookingData VARCHAR(100));
INSERT INTO Booking VALUES(1,'Booking 1'),(2,'Booking 2');
CREATE TABLE BookingInfo(BookingID INT CONSTRAINT FK_BookingInfo_BookingID FOREIGN KEY REFERENCES Booking(BookingID)
,SomeOtherInfo VARCHAR(100)
,FareDetails XML);
INSERT INTO BookingInfo VALUES
(1,'First row for ID=1, returns AP,AP'
,N'<AirFareInfo xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" IPFA="false">
<PTSDPFS>
<PTSD IO="false">
<FBC>AP</FBC>
</PTSD>
</PTSDPFS>
<PTSDPFS>
<PTSD IO="false">
<FBC>AP</FBC>
</PTSD>
</PTSDPFS>
</AirFareInfo>')
,(1,'Second row for ID=1, returns XY,MN'
,N'<AirFareInfo xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" IPFA="false">
<PTSDPFS>
<PTSD IO="false">
<FBC>XY</FBC>
</PTSD>
</PTSDPFS>
<PTSDPFS>
<PTSD IO="false">
<FBC>MN</FBC>
</PTSD>
</PTSDPFS>
</AirFareInfo>')
,(2,'row with ID=2, returns AA,BB'
,N'<AirFareInfo xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" IPFA="false">
<PTSDPFS>
<PTSD IO="false">
<FBC>AA</FBC>
</PTSD>
</PTSDPFS>
<PTSDPFS>
<PTSD IO="false">
<FBC>BB</FBC>
</PTSD>
</PTSDPFS>
</AirFareInfo>');
GO
——这就是功能。它返回as table
并且是完全内联的(没有BEGIN...END
!)
CREATE FUNCTION dbo.CreateBookingInfoCSV(@BookingID INT)
RETURNS TABLE
AS
RETURN
SELECT STUFF(
(
SELECT ','+REPLACE(FareDetails.query(N'data(/AirFareInfo/PTSDPFS/PTSD/FBC)').value(N'.',N'nvarchar(max)'),' ',',')
FROM BookingInfo AS bi
WHERE bi.BookingID=@BookingID
FOR XML PATH('')
),1,1,'') AS BookingInfoCSV;
GO
--Hint技巧与XQuery data() function
如果您的值包含空格,将会中断!
- 下列SELECT
调用所有行Booking
-表并获取配件详细信息
SELECT b.BookingID
,b.SomeBookingData
,A.BookingInfoCSV
FROM Booking AS b
OUTER APPLY dbo.CreateBookingInfoCSV(b.BookingID) AS A;
GO
- 清理 (小心真实数据!)
USE master;
GO
DROP DATABASE testDB;
- 结果
BookingID SomeBookingData BookingInfoCSV
1 Booking 1 AP,AP,XY,MN
2 Booking 2 AA,BB