Subject Re: [firebird-support] From Syntax - mine vs. Access
Author Arno Brinkman
Hi,

> Access: (note, I added the linebreak to make more readable)
> =======
> FROM
> Product INNER JOIN (
> CustOrder RIGHT JOIN (
> VisProdBatch INNER JOIN (
> VisItem INNER JOIN VisProdParent ON VisItem.ID = VisProdParent.VisItem
> ) ON VisProdBatch.ID = VisProdParent.VisProdBatch
> ) ON CustOrder.ID = VisItem.OrderNo) ON Product.ID = VisItem.Product

> Mine: (attempt 1)
> =======
> FROM
> VisItem
> JOIN VisProdParent ON VisItem.ID = VisProdParent.VisItem
> JOIN VisProdBatch ON VisProdBatch.ID = VisProdParent.VisProdBatch
> RIGHT JOIN CustOrder ON CustOrder.ID = VisItem.OrderNo
> JOIN Product ON Product.ID = VisItem.Product

I doubt the above queries return the same resultset.
Personally i prefer a LEFT JOIN above a RIGHT JOIN :

FROM
Product
JOIN VisItem ON (VisItem.Product = Product.ID)
JOIN VisProdParent ON (VisProdParent.VisItem = VisItem.ID)
JOIN VisProdBatch ON (VisProdBatch.ID = VisProdParent.VisProdBatch)
LEFT JOIN CustOrder ON (CustOrder.ID = VisItem.OrderNo)

Regards,
Arno Brinkman
ABVisie

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