>>>>Hi,
>>>>
>>>>This is a very newbie question, I know.
>>>>
>>>>I am trying to understand the SQL Select that Tamar Granor kindly helped me with. It has two JOIN clauses. And THEN, after the second JOIN, there are two ON clauses. I didn't know you can do it. I thought that ON should follow the JOIN immediately.
>>>>And looks like the first ON belong to the top (first) JOIN and the second ON belongs to the bottom (second) JOIN.
>>>>
>>>>My question is, how does SQL Server (or VFP for that matter) knows which ON apply to which JOIN?
>>>>
>>>>TIA
>>>
>>>For all I know, there is the following syntax:
>>>
>>>Syntax one: The ON follows the JOIN, from top to bottom
>>>
>>>SELECT * ;
>>>FROM Cur1 ;
>>> INNER JOIN Cur2 ;
>>> ON Cur1.Field=Cur2.Field ;
>>> ;
>>> INNER JOIN Cur3 ;
>>> ON Cur2.Field=Cur3.Field
>>>
>>>
>>>Syntax two: The ONs follows the JOINs, inside to outside
>>>
>>>SELECT *;
>>> FROM Cur1;
>>> INNER JOIN Cur2;
>>> INNER JOIN Cur3;
>>> ON Cur2.Field=Cur3.Field;
>>> ON Cur1.Field=Cur2.Field
>>>
>>>
>>>You are free to mix the styles. It might create a headache, but is it possible.
>>>
>>>Update: tab to space
>>
>>Lutz,
>>
>>Thank you very much for a clear example explaining my question. The second JOIN syntax was new to me.
>>But now I see that if there are two JOIN clauses, and the second JOIN syntax is used, the first ON must be applied to the first JOIN.
>
>??? The second example:
>The JOIN between Cur2 and Cur3 (ie the second JOIN) is the first or innermost ON (Cur2.Field=Cur3.Field). It might differ on different engines, but this at least is what VFP is doing. At one moment in time I switched some hundred views from 2 to 1 (while setting up the views to CA) , so there is remembrance of this.
In my case, this particular SQL Select will work only on MS SQL Server. I do not support VFP DB in this particular application.
And so far, I have been testing the approach suggested by Tamar, it works. Not that I doubt that a young and inexperienced person like Tamar could suggest a wrong approach :)
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