protected Expression VisitUnion(UnionExpression unionExpression)
{
var canOptimize = _canOptimize;
_canOptimize = false;
var source1 = (SelectExpression)Visit(unionExpression.Source1);
var source2 = (SelectExpression)Visit(unionExpression.Source2);
_canOptimize = canOptimize;
return(unionExpression.Update(source1, source2));
}
protected virtual void GenerateSetOperation(SetOperationBase setOperation)
{
string getSetOperation() => setOperation switch
{
ExceptExpression _ => "EXCEPT",
IntersectExpression _ => "INTERSECT",
UnionExpression _ => "UNION",
_ => throw new InvalidOperationException("Unknown SetOperationType."),
};
GenerateSetOperationOperand(setOperation, setOperation.Source1);
_relationalCommandBuilder.AppendLine();
_relationalCommandBuilder.AppendLine($"{getSetOperation()}{(setOperation.IsDistinct ? "" : " ALL")}");
GenerateSetOperationOperand(setOperation, setOperation.Source2);
}
protected Expression VisitUnion(UnionExpression unionExpression)
{
GenerateSetOperationHelper(unionExpression);
return(unionExpression);
}