Query + calculated field
lazarus / 16-Databases

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xinyiman · 2012-01-09 08:05

Hello guys, I have a query with a calculated field (product) which is
the product of the fields field1 and field2.
This query I want to show it in a DBGrid and if I change the values
​​of the cell that you want to update the value of the product. How do
I manage this calculated field?
Code: [Select]select campo1, campo2, (campo1*campo2) as prodotto FROM
Tabella;

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ludob · 2012-01-09 09:34

To do this you need to use calculated fields in the dataset. Change
your query to
Code: [Select]select campo1, campo2 FROM Tabella;
double click on the TSQLQuery and add a calculated field named
'prodotto', type Float (don't forget to add the 2 existing fields
campo1, campo2 if they aren't already defined. Click on the + sign to
get them from the fielddefs.). In TSQLQuery.OnCalcFields add
Code: [Select]SQLQuery1.FieldByName('prodotto').AsFloat:=SQLQuery1.Fie
ldByName('campo1').AsFloat * SQLQuery1.FieldByName('campo2 ').AsFloat

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xinyiman · 2012-01-09 10:06

Thank you