public static SqlQueryExpression Form(PlSqlParser.SubqueryContext context, out IntoClause into)
{
var query = Form(context.subqueryBasicElements(), out into);
var opPart = context.subquery_operation_part();
if (opPart.Length > 0) {
if (into != null)
throw new InvalidOperationException("Cannot SELECT INTO in a composite query.");
foreach (var part in opPart) {
CompositeFunction function;
if (part.MINUS() != null || part.EXCEPT() != null) {
function = CompositeFunction.Except;
} else if (part.UNION() != null) {
function = CompositeFunction.Union;
} else if (part.INTERSECT() != null) {
function = CompositeFunction.Intersect;
} else {
throw new ParseCanceledException("Invalid composite function.");
}
bool isAll = part.ALL() != null;
var next = Form(part.subqueryBasicElements());
var prev = query.NextComposite;
if (prev == null) {
prev = next;
} else {
prev.NextComposite = next;
}
query.IsCompositeAll = isAll;
query.CompositeFunction = function;
query.NextComposite = prev;
}
}
return query;
}