[Lazarus] Zeos Component Join Query

JoshyFun joshyfun at gmail.com
Tue Jan 12 18:54:49 CET 2010

Hello Lazarus-List,

Tuesday, January 12, 2010, 6:07:37 PM, you wrote:

MF> I got an *sql logic error* trying to execute following query using Zeos
MF> Component (ZQuery):
MF> "SELECT Invoices.*, Customers.Name
MF>  FROM Invoices
MF>  LEFT JOIN Customers
MF>  ON Invoices.CustomerID= Customers.ID
MF> * WHERE Customers.Name = 'Tom' "*
MF> excluding the Where clause make the query run without problems.

From my point of view it is a "SQL logic error", I think it should be:

"SELECT Invoices.*, Customers.Name
 FROM Customers
 RIGHT JOIN Invoices
 ON Invoices.CustomerID= Customers.ID
 WHERE Customers.Name = 'Tom' "

Note the swapping of Customers and Invoices, the other way the SQL
engine will sequentially scan all invoices to join them with customer
and perform the "where". Anyway I do not know why ZQuery raises and
exception :-? (I'm not using Zeos at all).

Best regards,

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