Hi,

I am struggling a bit trying to compare an expression to a constant value, as in the following SQL query:

SELECT *
FROM property p
INNER JOIN currency c ON c.ID = p.CurrencyID
WHERE (p.Price / c.ExRate) > 1000

I have tried the following (adapted from the manual, and a bit of a stab in the dark..) but it doesn't work:

IExpression leftOperand = new Expression(PropertyFields.Price, ExOp.Div, CurrencyFields.ExRate);
IExpression rightOperand = new Expression(1000, ExOp.None, (IEntityFieldCore)null);
IEntityField2 field = PropertyFields.Price.SetExpression(leftOperand);
IPredicate priceFilter = new FieldCompareExpressionPredicate(field, null, ComparisonOperator.GreaterEqual, rightOperand);

filter.PredicateExpression.Add(priceFilter);

Searching the forums, I thought I'd found my answer in: http://www.llblgen.com/tinyforum/Messages.aspx?ThreadID=8765

...but the suggestion given there won't compile:

IPredicate filter = ((PropertyFields.Price / CurrencyFields.ExRate) > 1000);

The compiler says "Operator '>' cannot be applied to operands of type 'SD.LLBLGen.Pro.ORMSupportClasses.Expression' and 'int'"

I feel like I'm missing something obvious here but whatever combination of expression and field objects I combine I can't quite get it. If anybody knows how to do this I'd be most grateful!

I'm using 2.6 Final, adapter, .NET 3.5, MySql 5.0

Thanks in advance, Dan

Try the following:

IExpression exp = new Expression(PropertyFields.Price, ExOp.Div, CurrencyFields.ExRate);

IEntityField2 field = PropertyFields.Price.SetExpression(exp);

filter.PredicateExpression.Add(field > 1000);

That does that trick...almost. I still get the same compilation error. But if I declare 'field' as an EntityField2 instead of an IEntityField2 it compiles fine.

IExpression exp = new Expression(PropertyFields.Price, ExOp.Div, CurrencyFields.ExRate);

EntityField2 field = PropertyFields.Price.SetExpression(exp);

filter.PredicateExpression.Add(field > 1000);

Thanks for the help, Walaa!

You are welcomed