如何显示其他表中是否存在字段？

Question

我想显示/显示每次交易是否找到产品。

tblProducts

ID     PRODCODE    PRODDESC
1      PFX-321     MILK CHOCO
2      PDF-875     COFFEE JELLY
3      PWA-718     MILK SHAKE

tblTransactions

TCODE       PRODCODE
BMX2213391  PFX-321
BMX2213391  PDF-875
PDFSD92851  PDF-875

我希望结果显示如下

TCODE       PRODCODE    FOUND
BMX2213391  PFX-321     YES
BMX2213391  PDF-875     YES
BMX2213391  PWA-718     NO
PDFSD92851  PFX-321     NO
PDFSD92851  PDF-875     YES
PDFSD92851  PWA-718     NO

我试过，INNER JOIN，FULL OUTER JOIN，LEFT JOIN和RIGHT JOIN但是我没有得到我需要的确切数据。

以下是我测试的查询。

SELECT * FROM tblProducts a INNER JOIN tblTransactions b ON a.PRODCODE = b.PRODCODE
SELECT * FROM tblProducts a FULL OUTER JOIN tblTransactions b ON a.PRODCODE = b.PRODCODE
SELECT * FROM tblProducts a LEFT JOIN tblTransactions b ON a.PRODCODE = b.PRODCODE
SELECT * FROM tblProducts a RIGHT JOIN tblTransactions b ON a.PRODCODE = b.PRODCODE

Answer 1

我非常确定这是有效的 - SQLFiddle在这里：http://sqlfiddle.com/#!3/65eb1/23

WITH AllVals AS 
(SELECT a.PRODCODE, b.TCODE
FROM tblProducts a
CROSS JOIN tblTransactions b)

SELECT DISTINCT c.PRODCODE,
  c.TCODE,
  CASE WHEN d.PRODCODE IS NULL THEN 'NO' ELSE 'YES' END AS FOUND
FROM AllVals c
LEFT OUTER JOIN tblTransactions d
ON c.PRODCODE = d.PRODCODE
AND c.TCODE = d.TCODE

Answer 2

http://sqlfiddle.com/#!3/65eb1/24

select DT.TCODE, DT.PRODCODE, case when (Tr2.TCODE IS null and Tr2.PRODCODE IS null) then 'No' else 'Yes' END as FOUND
 from tblTransactions Tr2 right join 
(
select distinct Tr.TCODE, p.PRODCODE               
from   tblProducts p  cross join tblTransactions Tr
) DT
on DT.PRODCODE = Tr2.PRODCODE and DT.TCODE = Tr2.TCODE;