Method visitASTSelectQuery

src/Optimizer/QueryUseOptimizerChecker.cpp:240–286

}

bool QueryUseOptimizerVisitor::visitASTSelectQuery(ASTPtr & node, QueryUseOptimizerContext & context)
{
    auto * select = node->as<ASTSelectQuery>();

    if (select->limit_with_ties)
    {
        reason = "LIMIT/OFFSET FETCH WITH TIES not implemented";
        return false;
    }

    if (context.disallow_subquery)
    {
        reason = "nullIn/globalNullIn/notNullIn/globalNotNullIn function with subquery not implemented";
        return false;
    }

    if (select->group_by_with_totals && context.disallow_with_totals)
    {
        reason = "group by with totals only supports with totals at outmost select";
        return false;
    }
    auto has_join = [](const auto & sel_query) { return sel_query.tables() && sel_query.tables()->children.size() > 1; };

    QueryUseOptimizerContext child_context{.context = context.context, .ctes = context.ctes, .disallow_with_totals = has_join(*select)};
    collectWithTableNames(*select, child_context.ctes);

    for (const auto * table_expression : getTableExpressions(*select))
    {
        if (!checkDatabaseAndTable(*table_expression, child_context.context, child_context.ctes))
        {
            reason = "unsupported storage: " + table_expression->formatForErrorMessage();
            return false;
        }
        if (table_expression->table_function)
        {
            const auto & function = table_expression->table_function->as<ASTFunction &>();

            if (function.name == "fusionMerge")
                return true;

            reason = "table function";
            return false;
        }
    }

    return visitNode(node, child_context);
}

bool QueryUseOptimizerVisitor::visitASTTableJoin(ASTPtr & node, QueryUseOptimizerContext & context)
{