presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitExists
class AstBuilder:    @Override
    public Node visitExists(SqlBaseParser.ExistsContext context)
    {
        return new ExistsPredicate(getLocation(context), new SubqueryExpression(getLocation(context), (Query) visit(context.query())));
    }