LEFT JOIN两个表

Question

I have two lists Tender and Tender Items. Tender list contains column 'Tender Name', 'Tender Description'. Second list Tender Items contains columns 'Item Name', 'Item Price' and a lookup column 'Tender Name' from 1st list Tender.

There may be that A Tender contains any items or not. So I want to get the left join of these two lists so that I can get each Tender with items if any. Below is the join of two lists that I want to achieve.

First list Tender contains 3 tenders. and second list Tender items contain 2 items. Below is the left join of the two lists where "tender 3" has no item:

  Tender Name, Tender Description, Item Name, Item Price.

  tender 1,tender desc1, item1, 500

  tender 2, tender desc2,item2, 400

  tender 3,tender desc3,NULL,NULL

How can I achieve this above result?

Answer 1

SELECT T.TENDERNAME, T.TENDERDESC, TI.ITEMNAME, TI.ITEMPRICE
FROM TENDERS T LEFT JOIN TENDERITEMS TI
ON T.TENDERNAME = TI.TENDERNAME

You would be better off defining an integral key for Tenders and then using that value as a foreign key in TenderItems. If you change the tender name, the link between the tender and its items would be lost.