public override IASTNode VisitAggregationFunction(SqlServerCommandParser.AggregationFunctionContext context)
{
var aggregationType = context.aggregationFunctionName().GetText();
return(AggregationType.IsAggregationType(aggregationType)
? CreateAggregationSegment(context, aggregationType)
: new ExpressionProjectionSegment(context.Start.StartIndex, context.Stop.StopIndex, context.GetText()));
}
private string GetDistinctExpression(SqlServerCommandParser.AggregationFunctionContext context)
{
StringBuilder result = new StringBuilder();
for (int i = 3; i < context.ChildCount - 1; i++)
{
result.Append(context.GetChild(i).GetText());
}
return(result.ToString());
}
private IASTNode CreateAggregationSegment(SqlServerCommandParser.AggregationFunctionContext context, string aggregationType)
{
var type = AggregationType.ValueOf(aggregationType.ToUpper());
int innerExpressionStartIndex = ((ITerminalNode)context.GetChild(1)).Symbol.StartIndex;
if (null == context.distinct())
{
return(new AggregationProjectionSegment(context.Start.StartIndex, context.Stop.StopIndex, type, innerExpressionStartIndex));
}
return(new AggregationDistinctProjectionSegment(context.Start.StartIndex, context.Stop.StopIndex, type, innerExpressionStartIndex, GetDistinctExpression(context)));
}