work on order by began

Readme.md

@@ -1,7 +1,9 @@
 
 ### TODO
-- support for *
 - support for order by, offset, limit
+- support for btree indexes
+- support for parenthesis
+- support for *
 - add pipe | token
 - add count min and max functions, eg aggregate functions
 - maybe to create iterator on table

lexer.cpp

@@ -119,115 +119,86 @@ namespace usql {
 	    // TODO, FIXME 'one is evaluated as identifier
 	    if (token == ";")
 		    return TokenType::semicolon;
-
 	    if (token == "+")
 		    return TokenType::plus;
-
 	    if (token == "-")
 		    return TokenType::minus;
-
 	    if (token == "*")
 		    return TokenType::multiply;
-
 	    if (token == "/")
 		    return TokenType::divide;
-
 	    if (token == "(")
 		    return TokenType::open_paren;
-
 	    if (token == ")")
 		    return TokenType::close_paren;
-
 	    if (token == "=")
 		    return TokenType::equal;
-
 	    if (token == "!=")
 		    return TokenType::not_equal;
-
 	    if (token == ">")
 		    return TokenType::greater;
-
 	    if (token == ">=")
 		    return TokenType::greater_equal;
-
 	    if (token == "<")
 		    return TokenType::lesser;
-
 	    if (token == "<=")
 		    return TokenType::lesser_equal;
-
 	    if (token == "as")
 		    return TokenType::keyword_as;
-
 	    if (token == "create")
 		    return TokenType::keyword_create;
-
 	    if (token == "drop")
 		    return TokenType::keyword_drop;
-
 	    if (token == "where")
 		    return TokenType::keyword_where;
-
+	    if (token == "order")
+		    return TokenType::keyword_order;
+	    if (token == "by")
+		    return TokenType::keyword_by;
+	    if (token == "asc")
+		    return TokenType::keyword_asc;
+	    if (token == "desc")
+		    return TokenType::keyword_desc;
 	    if (token == "from")
 		    return TokenType::keyword_from;
-
 	    if (token == "delete")
 		    return TokenType::keyword_delete;
-
 	    if (token == "table")
 		    return TokenType::keyword_table;
-
 	    if (token == "insert")
 		    return TokenType::keyword_insert;
-
 	    if (token == "into")
 		    return TokenType::keyword_into;
-
 	    if (token == "values")
 		    return TokenType::keyword_values;
-
 	    if (token == "select")
 		    return TokenType::keyword_select;
-
 	    if (token == "set")
 		    return TokenType::keyword_set;
-
 	    if (token == "copy")
 		    return TokenType::keyword_copy;
-
 	    if (token == "update")
 		    return TokenType::keyword_update;
-
 	    if (token == "load")
 		    return TokenType::keyword_load;
-
 	    if (token == "save")
 		    return TokenType::keyword_save;
-
 	    if (token == "not")
 		    return TokenType::keyword_not;
-
 	    if (token == "null")
 		    return TokenType::keyword_null;
-
 	    if (token == "integer")
 		    return TokenType::keyword_integer;
-
 	    if (token == "float")
 		    return TokenType::keyword_float;
-
 	    if (token == "varchar")
 		    return TokenType::keyword_varchar;
-
 	    if (token == "or")
 		    return TokenType::logical_or;
-
 	    if (token == "and")
 		    return TokenType::logical_and;
-
 	    if (token == ",")
 		    return TokenType::comma;
-
 	    if (token == "\n" || token == "\r\n" || token == "\r")
 		    return TokenType::newline;
 
@@ -347,6 +318,18 @@ namespace usql {
 		    case TokenType::keyword_where:
 			    txt = "where";
 			    break;
+		    case TokenType::keyword_order:
+			    txt = "order";
+			    break;
+		    case TokenType::keyword_by:
+			    txt = "by";
+			    break;
+		    case TokenType::keyword_asc:
+			    txt = "asc";
+			    break;
+		    case TokenType::keyword_desc:
+			    txt = "desc";
+			    break;
 		    case TokenType::keyword_table:
 			    txt = "table";
 			    break;

lexer.h

@@ -25,6 +25,10 @@ namespace usql {
 	keyword_drop,
 	keyword_table,
 	keyword_where,
+	keyword_order,
+	keyword_by,
+	keyword_asc,
+	keyword_desc,
 	keyword_delete,
 	keyword_update,
 	keyword_load,

main.cpp

@@ -9,7 +9,7 @@ int main(int argc, char *argv[]) {
 	std::vector<std::string> sql_commands{
 		    "create table a (i integer not null, s varchar(64), f float null)",
 		    "insert into a (i, s) values(1, upper('one'))",
-		    "update table a set s = 'null string aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'",
+//		    "update table a set s = 'null string aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'",
 //		    "update table a set i = null",
 		    "insert into a (i, s) values(2, 'two')",
 		    "insert into a (i, s) values(3, 'two')",
@@ -17,30 +17,30 @@ int main(int argc, char *argv[]) {
 		    "insert into a (i, s) values(5, 'five')",
 		    "insert into a (i, s) values(to_date('20.12.1973', '%d.%m.%Y'), 'six')",
 		    "save table a into '/tmp/a.csv'",
-		    "select i, s from a where i > 2",
+		    "select i, s from a where i > 2 order by 1 desc"
-		    "select i, s from a where i = 1",
+//		    "select i, s from a where i = 1",
-		    "select i, s from a where s = 'two'",
+//		    "select i, s from a where s = 'two'",
-		    "select i, s from a where i <= 3 and s = 'one'",
+//		    "select i, s from a where i <= 3 and s = 'one'",
-		    "select i, s from a where i > 0",
+//		    "select i, s from a where i > 0",
-		    "delete from a where i = 4",
+//		    "delete from a where i = 4",
-		    "select i, s from a where i > 0",
+//		    "select i, s from a where i > 0",
-		    "update a set f = 9.99 where i = 3",
+//		    "update a set f = 9.99 where i = 3",
-		    "select i, s, f from a where i = 3",
+//		    "select i, s, f from a where i = 3",
-		    "update a set s = 'three', f = f + 0.01 where i = 3",
+//		    "update a set s = 'three', f = f + 0.01 where i = 3",
-		    "select i, s, f from a where i = 3",
+//		    "select i, s, f from a where i = 3",
-		    "create table data (ticker varchar(8), price float null)",
+//		    "create table data (ticker varchar(8), price float null)",
-		    "load data from '/Users/vaclavt/Library/Mobile Documents/com~apple~CloudDocs/Development/usql/data.csv')",
+//		    "load data from '/Users/vaclavt/Library/Mobile Documents/com~apple~CloudDocs/Development/usql/data.csv')",
-		    "select ticker, price from data",
+//		    "select ticker, price from data",
-		    "select i, s, f from a where i < 300",
+//		    "select i, s, f from a where i < 300",
-		    "create table x as select i, s, f from a where i < 300",
+//		    "create table x as select i, s, f from a where i < 300",
-		    "select i, s, f from x where i < 300",
+//		    "select i, s, f from x where i < 300",
-		    "drop table x",
+//		    "drop table x",
-		    "select i, s, f from a where i > 300",
+//		    "select i, s, f from a where i > 300",
-		    "select i, to_string(i, '%d.%m.%Y'), s, f from a where i > 300",
+//		    "select i, to_string(i, '%d.%m.%Y'), s, f from a where i > 300",
-		    "create table prices (datetime integer, symbol varchar(8), prev_close float, open float, price float, change float, change_prct varchar(16))",
+//		    "create table prices (datetime integer, symbol varchar(8), prev_close float, open float, price float, change float, change_prct varchar(16))",
-		    "load prices from '/Users/vaclavt/Library/Mobile Documents/com~apple~CloudDocs/Development/usql/prices.csv'",
+//		    "load prices from '/Users/vaclavt/Library/Mobile Documents/com~apple~CloudDocs/Development/usql/prices.csv'",
-		    "insert into prices (datetime, symbol, prev_close, open, price, change, change_prct) values (1626979443, 'MPC', 54.08, 53.82, 53.63, -0.832101, '-0.83 %')",
+//		    "insert into prices (datetime, symbol, prev_close, open, price, change, change_prct) values (1626979443, 'MPC', 54.08, 53.82, 53.63, -0.832101, '-0.83 %')",
-		    "select to_string(datetime, '%d.%m.%Y %H:%M:%S'), symbol, prev_close, open, price, change, change_prct from prices where symbol = 'SYF'"
+//		    "select to_string(datetime, '%d.%m.%Y %H:%M:%S'), symbol, prev_close, open, price, change, change_prct from prices where symbol = 'SYF'"
 	};
 
 

parser.cpp

@@ -235,11 +235,12 @@ std::unique_ptr<Node> Parser::parse_select_from_table() {
 
 	std::unique_ptr<Node> where_node = parse_where_clause();
 
-//    if (m_lexer.tokenType() == TokenType::keyword_order_by) {}
+	std::vector<ColOrderNode> orderby_node = parse_orderby_clause();
+
 //    if (m_lexer.tokenType() == TokenType::keyword_offset) {}
 //    if (m_lexer.tokenType() == TokenType::keyword_limit) {}
 
-	return std::make_unique<SelectFromTableNode>(table_name, std::move(cols), std::move(where_node));
+	return std::make_unique<SelectFromTableNode>(table_name, std::move(cols), std::move(where_node), orderby_node);
     }
 
     std::unique_ptr<Node> Parser::parse_delete_from_table() {
@@ -291,9 +292,6 @@ std::unique_ptr<Node> Parser::parse_select_from_table() {
     }
 
     std::unique_ptr<Node> Parser::parse_where_clause() {
-	    // TODO add support for multiple filters
-	    // TODO add support for parenthesis
-
 	if (m_lexer.tokenType() != TokenType::keyword_where) {
 		return std::make_unique<TrueNode>();
 	}
@@ -308,11 +306,50 @@ std::unique_ptr<Node> Parser::parse_select_from_table() {
 			std::unique_ptr<Node> node2 = parse_relational_expression();
 			node = std::make_unique<LogicalOperatorNode>(operation, std::move(node), std::move(node2));
 		}
-	    } while (m_lexer.tokenType() != TokenType::eof);    // until whole where clause parsed
+	} while (m_lexer.tokenType() != TokenType::eof && m_lexer.tokenType() != TokenType::keyword_order);
 
 	return node;
     }
 
+
+    std::vector<ColOrderNode>  Parser::parse_orderby_clause() {
+	std::vector<ColOrderNode> order_cols;
+	
+	if (m_lexer.tokenType() == TokenType::keyword_order) {
+		m_lexer.skipToken(TokenType::keyword_order);
+		m_lexer.skipToken(TokenType::keyword_by);
+
+		do {
+			int col_index  = -1;
+			bool asc = true;
+			
+			auto token_type = m_lexer.tokenType();
+			std::string tokenString = m_lexer.consumeCurrentToken().token_string;
+			switch (token_type) {
+			case TokenType::int_number:
+				col_index = std::stoi(tokenString);
+				break;
+			default:
+				throw Exception("column index alloved in order by clause at this moment");
+			}
+
+			if (m_lexer.tokenType() == TokenType::keyword_asc) {
+				m_lexer.skipToken(TokenType::keyword_asc);
+			} else if (m_lexer.tokenType() == TokenType::keyword_desc) {
+				m_lexer.skipToken(TokenType::keyword_desc);
+				asc = false;
+			}
+
+			order_cols.push_back(ColOrderNode{col_index, asc});
+
+			m_lexer.skipTokenOptional(TokenType::comma);
+
+		} while (m_lexer.tokenType() != TokenType::eof);	// && m_lexer.tokenType() != TokenType::keyword_offset && m_lexer.tokenType() != TokenType::keyword_limit);
+    	}
+	    
+	return order_cols;
+    }
+
     std::unique_ptr<Node> Parser::parse_relational_expression() {
 	    auto left = parse_operand_node();
 	    auto operation = parse_relational_operator();
@@ -336,7 +373,7 @@ std::unique_ptr<Node> Parser::parse_select_from_table() {
 			    return std::make_unique<DatabaseValueNode>(tokenString);
 		    case TokenType::keyword_null:
 		    	return std::make_unique<NullValueNode>();
-		    default:;
+		    default:
 			    throw Exception("Unknown operand node");
 	    }
     }

parser.h

@@ -34,6 +34,7 @@ namespace usql {
 	save_table,
 	drop_table,
 	column_name,
+	column_order,
 	column_value,
 	function,
 	column_def,
@@ -52,6 +53,15 @@ namespace usql {
 	ColNameNode(const std::string col_name) : Node(NodeType::column_name), name(col_name) {}
     };
 
+    struct ColOrderNode : Node {
+	std::string col_name;
+	int col_index;
+	bool ascending;
+
+	ColOrderNode(const std::string name, bool asc) : Node(NodeType::column_order), col_name(name), col_index(-1), ascending(asc) {}
+	ColOrderNode(int index, bool asc) : Node(NodeType::column_name), col_name(""), col_index(index), ascending(asc) {}
+    };
+
     struct SelectColNode : Node {
         std::unique_ptr<Node>	value;
         std::string name;
@@ -216,9 +226,10 @@ namespace usql {
 	std::string table_name;
 	std::unique_ptr<std::vector<SelectColNode>> cols_names;
 	std::unique_ptr<Node> where;
+	std::vector<ColOrderNode> order_by;
 
-	SelectFromTableNode(std::string name, std::unique_ptr<std::vector<SelectColNode>> names, std::unique_ptr<Node> where_clause) :
+	SelectFromTableNode(std::string name, std::unique_ptr<std::vector<SelectColNode>> names, std::unique_ptr<Node> where_clause, std::vector<ColOrderNode> orderby) :
-	Node(NodeType::select_from), table_name(name), cols_names(std::move(names)), where(std::move(where_clause)) {}
+	Node(NodeType::select_from), table_name(name), cols_names(std::move(names)), where(std::move(where_clause)), order_by(orderby) {}
     };
 
     struct CreateTableAsSelectNode : Node {
@@ -292,6 +303,8 @@ namespace usql {
 	std::unique_ptr<Node> parse_update_table();
 
 	std::unique_ptr<Node> parse_where_clause();
+	std::vector<ColOrderNode>  parse_orderby_clause();
+
 	std::unique_ptr<Node> parse_operand_node();
 	std::unique_ptr<Node> parse_value();
 	RelationalOperatorType parse_relational_operator();

table.cpp

@@ -21,6 +21,13 @@ ColDefNode Table::get_column_def(const std::string &col_name) {
 	}
 }
 
+ColDefNode Table::get_column_def(int col_index) {
+	if (col_index >= 0 && col_index < columns_count()) {
+		return m_col_defs[col_index];
+	} else {
+		throw Exception("column with this index does not exists (" + std::to_string(col_index) + ")");
+	}
+}
 
 Row Table::create_empty_row() {
 	return Row(columns_count());

table.h

@@ -14,6 +14,7 @@ namespace usql {
 	Table(const std::string name, const std::vector<ColDefNode> columns);
 
 	ColDefNode get_column_def(const std::string &col_name);
+	ColDefNode get_column_def(int col_index);
 
 	int columns_count() const { return m_col_defs.size(); };
 

usql.cpp

@@ -155,8 +155,7 @@ std::unique_ptr<Table> USql::execute_select(SelectFromTableNode &node) {
 	std::vector<int> source_table_col_index{};
 
 	for (int i = 0; i < node.cols_names->size(); i++) {
-		auto [ src_tbl_col_index, rst_tbl_col_def ]  = get_column_definition(table,
+		auto [ src_tbl_col_index, rst_tbl_col_def ]  = get_column_definition(table, &node.cols_names->operator[](i), i);
-										     &node.cols_names->operator[](i), i);
 
 		source_table_col_index.push_back(src_tbl_col_index);
 		result_tbl_col_defs.push_back(rst_tbl_col_def);
@@ -176,8 +175,7 @@ std::unique_ptr<Table> USql::execute_select(SelectFromTableNode &node) {
 				auto row_col_index = source_table_col_index[idx];
 
 				if (row_col_index == -1) {	// TODO introduce constant here
-					auto evaluated_value = eval_value_node(table, *row, node.cols_names->operator[](
+					auto evaluated_value = eval_value_node(table, *row, node.cols_names->operator[](idx).value.get());
-						    idx).value.get());
 					ValueNode *col_value = evaluated_value.get();
 
 					new_row.setColumnValue(&result_tbl_col_defs[idx], col_value);
@@ -192,9 +190,51 @@ std::unique_ptr<Table> USql::execute_select(SelectFromTableNode &node) {
 		}
 	}
 
+	// order by
+	execute_order_by(node, table, result);
+
+
 	return std::move(result);
 }
 
+void USql::execute_order_by(SelectFromTableNode &node, Table *table, std::__unique_if<Table>::__unique_single &result) const {
+	if (node.order_by.size() == 0) return;
+
+	auto compare_rows = [&node, &table, this](const Row &a, const Row &b) {
+		for(auto order_by_col_def : node.order_by) {
+			ColDefNode col_def = table->get_column_def(order_by_col_def.col_index - 1);	 // TODO validate index
+			ColValue *a_val = a.ith_column(col_def.order);
+			ColValue *b_val = b.ith_column(col_def.order);
+
+			if (a_val->isNull() && b_val->isNull()) return true;	// both is null so a goes to end
+			if (!a_val->isNull() && b_val->isNull()) return true;	// b is null so goes to end
+			if (a_val->isNull() && !b_val->isNull()) return false;	// a is null so goes to end
+
+			int compare = compare_col_values(col_def, a_val, b_val);
+			if (compare < 0) return order_by_col_def.ascending ? true : false;
+			if (compare > 0) return order_by_col_def.ascending ? false : true;
+		}
+	     return false;
+	};
+
+	result->m_rows.sort(compare_rows);
+}
+
+int USql::compare_col_values(const ColDefNode &col_def, ColValue *a_val, ColValue *b_val) const {
+	double c;
+	switch (col_def.type) {
+		case (ColumnType::integer_type):
+			return a_val->getIntValue() - b_val->getIntValue();
+		case (ColumnType::float_type):
+			 c = a_val->getDoubleValue() - b_val->getDoubleValue();
+			 return c < 0 ? -1 : c==0.0 ? 0 : 1; 
+		case (ColumnType::varchar_type):
+			return a_val->getStringValue().compare(b_val->getStringValue());
+		default: 
+			throw Exception("Unsupported data type");
+	}
+}
+
 std::tuple<int, ColDefNode> USql::get_column_definition(Table *table, SelectColNode *select_col_node, int col_order ) {
 	std::string new_col_name = select_col_node->name;
 

usql.h

@@ -54,6 +54,11 @@ private:
 private:
     Parser m_parser;
     std::list<Table> m_tables;
+
+    int compare_col_values(const ColDefNode &col_def, ColValue *a_val, ColValue *b_val) const;
+
+    void
+    execute_order_by(SelectFromTableNode &node, Table *table, std::__unique_if<Table>::__unique_single &result) const;
 };
 
 }	// namespace