TD-13338 SELECT statement translate code

include/nodes/nodes.h

@@ -78,6 +78,11 @@ typedef struct SNodeList {
   SListCell* pTail;
 } SNodeList;
 
+typedef struct SNameStr {
+  int32_t len;
+  char* pName;
+} SNameStr;
+
 typedef struct SDataType {
   uint8_t type;
   uint8_t precision;
@@ -89,6 +94,7 @@ typedef struct SExprNode {
   ENodeType nodeType;
   SDataType resType;
   char aliasName[TSDB_COL_NAME_LEN];
+  SNodeList* pAssociationList;
 } SExprNode;
 
 typedef enum EColumnType {
@@ -102,7 +108,9 @@ typedef struct SColumnNode {
   EColumnType colType; // column or tag
   char dbName[TSDB_DB_NAME_LEN];
   char tableName[TSDB_TABLE_NAME_LEN];
+  char tableAlias[TSDB_TABLE_NAME_LEN];
   char colName[TSDB_COL_NAME_LEN];
+  SNode* pProjectRef;
 } SColumnNode;
 
 typedef struct SValueNode {
@@ -176,13 +184,16 @@ typedef struct SFunctionNode {
 
 typedef struct STableNode {
   ENodeType type;
+  char dbName[TSDB_DB_NAME_LEN];
   char tableName[TSDB_TABLE_NAME_LEN];
-  char tableAliasName[TSDB_COL_NAME_LEN];
+  char tableAlias[TSDB_TABLE_NAME_LEN];
 } STableNode;
 
+struct STableMeta;
+
 typedef struct SRealTableNode {
   STableNode table; // QUERY_NODE_REAL_TABLE
-  char dbName[TSDB_DB_NAME_LEN];
+  struct STableMeta* pMeta;
 } SRealTableNode;
 
 typedef struct STempTableNode {
@@ -273,7 +284,6 @@ typedef struct SFillNode {
 typedef struct SSelectStmt {
   ENodeType type; // QUERY_NODE_SELECT_STMT
   bool isDistinct;
-  bool isStar;
   SNodeList* pProjectionList; // SNode
   SNode* pFromTable;
   SNode* pWhere;
@@ -295,6 +305,8 @@ typedef struct SSetOperator {
   ESetOperatorType opType;
   SNode* pLeft;
   SNode* pRight;
+  SNodeList* pOrderByList; // SOrderByExprNode
+  SNode* pLimit;
 } SSetOperator;
 
 SNode* nodesMakeNode(ENodeType type);
@@ -306,8 +318,10 @@ void nodesDestroyList(SNodeList* pList);
 
 typedef bool (*FQueryNodeWalker)(SNode* pNode, void* pContext);
 
-bool nodesWalkNode(SNode* pNode, FQueryNodeWalker walker, void* pContext);
-bool nodesWalkList(SNodeList* pList, FQueryNodeWalker walker, void* pContext);
+void nodesWalkNode(SNode* pNode, FQueryNodeWalker walker, void* pContext);
+void nodesWalkList(SNodeList* pList, FQueryNodeWalker walker, void* pContext);
+void nodesWalkNodePostOrder(SNode* pNode, FQueryNodeWalker walker, void* pContext);
+void nodesWalkListPostOrder(SNodeList* pList, FQueryNodeWalker walker, void* pContext);
 
 bool nodesWalkStmt(SNode* pNode, FQueryNodeWalker walker, void* pContext);
 

include/util/taoserror.h

@@ -440,7 +440,10 @@ int32_t* taosGetErrno();
 #define TSDB_CODE_SCH_STATUS_ERROR              TAOS_DEF_ERROR_CODE(0, 0x2501)  //scheduler status error
 #define TSDB_CODE_SCH_INTERNAL_ERROR            TAOS_DEF_ERROR_CODE(0, 0x2502)  //scheduler internal error
 
-
+//parser
+#define TSDB_CODE_PARSER_INVALID_COLUMN         TAOS_DEF_ERROR_CODE(0, 0x2601)  //invalid column name
+#define TSDB_CODE_PARSER_TABLE_NOT_EXIST        TAOS_DEF_ERROR_CODE(0, 0x2602)  //table not exist
+#define TSDB_CODE_PARSER_AMBIGUOUS_COLUMN       TAOS_DEF_ERROR_CODE(0, 0x2603)  //ambiguous column
 
 #ifdef __cplusplus
 }

source/libs/parser/src/astCreateFuncs.c

@@ -150,7 +150,7 @@ SNode* createRealTableNode(SAstCreateContext* pCxt, const SToken* pDbName, const
   SRealTableNode* realTable = (SRealTableNode*)nodesMakeNode(QUERY_NODE_REAL_TABLE);
   CHECK_OUT_OF_MEM(realTable);
   if (NULL != pDbName) {
-    strncpy(realTable->dbName, pDbName->z, pDbName->n);
+    strncpy(realTable->table.dbName, pDbName->z, pDbName->n);
   }
   strncpy(realTable->table.tableName, pTableName->z, pTableName->n);
   return (SNode*)realTable;
@@ -288,9 +288,6 @@ SNode* createSelectStmt(SAstCreateContext* pCxt, bool isDistinct, SNodeList* pPr
   SSelectStmt* select = (SSelectStmt*)nodesMakeNode(QUERY_NODE_SELECT_STMT);
   CHECK_OUT_OF_MEM(select);
   select->isDistinct = isDistinct;
-  if (NULL == pProjectionList) {
-    select->isStar = true;
-  }
   select->pProjectionList = pProjectionList;
   select->pFromTable = pTable;
   return (SNode*)select;

source/libs/parser/src/astTranslate.c

-/*
- * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
- *
- * This program is free software: you can use, redistribute, and/or modify
- * it under the terms of the GNU Affero General Public License, version 3
- * or later ("AGPL"), as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-// int32_t doTranslate() {
-
-// }

source/libs/parser/src/parserImpl.c

@@ -15,8 +15,9 @@
 
 #include "parserImpl.h"
 
-#include "ttoken.h"
 #include "astCreateContext.h"
+#include "parserInt.h"
+#include "ttoken.h"
 
 typedef void* (*FMalloc)(size_t);
 typedef void (*FFree)(void*);
@@ -25,7 +26,7 @@ extern void* NewParseAlloc(FMalloc);
 extern void NewParse(void*, int, SToken, void*);
 extern void NewParseFree(void*, FFree);
 
-uint32_t toNewTokenId(uint32_t tokenId) {
+static uint32_t toNewTokenId(uint32_t tokenId) {
   switch (tokenId) {
     case TK_UNION:
       return NEW_TK_UNION;
@@ -73,7 +74,7 @@ uint32_t toNewTokenId(uint32_t tokenId) {
   return tokenId;
 }
 
-uint32_t getToken(const char* z, uint32_t* tokenId) {
+static uint32_t getToken(const char* z, uint32_t* tokenId) {
   uint32_t n = tGetToken(z, tokenId);
   *tokenId = toNewTokenId(*tokenId);
   return n;
@@ -137,3 +138,289 @@ abort_parse:
   pQuery->pRoot = cxt.pRootNode;
   return cxt.valid ? TSDB_CODE_SUCCESS : TSDB_CODE_FAILED;
 }
+
+// typedef struct SNamespace {
+//   int16_t level; // todo for correlated subquery
+//   char dbName[TSDB_DB_NAME_LEN];
+//   char tableAlias[TSDB_TABLE_NAME_LEN];
+//   SHashObj* pColHash; // key is colname, value is index of STableMeta.schema
+//   STableMeta* pMeta;
+// } SNamespace;
+
+typedef struct STranslateContext {
+  SParseContext* pParseCxt;
+  int32_t errCode;
+  SMsgBuf msgBuf;
+  SArray* pNsLevel; // element is SArray*, the element of this subarray is STableNode*
+  int32_t currLevel;
+} STranslateContext;
+
+static int32_t translateSubquery(STranslateContext* pCxt, SNode* pNode);
+
+static char* getSyntaxErrFormat(int32_t errCode) {
+  switch (errCode) {
+    case TSDB_CODE_PARSER_INVALID_COLUMN:
+      return "Invalid column name : %s";
+    case TSDB_CODE_PARSER_TABLE_NOT_EXIST:
+      return "Table does not exist : %s";
+    case TSDB_CODE_PARSER_AMBIGUOUS_COLUMN:
+      return "Column ambiguously defined : %s";
+    default:
+      return "Unknown error";
+  }
+}
+
+static int32_t generateSyntaxErrMsg(STranslateContext* pCxt, int32_t errCode, const char* additionalInfo) {
+  snprintf(pCxt->msgBuf.buf, pCxt->msgBuf.len, getSyntaxErrFormat(errCode), additionalInfo);
+  pCxt->errCode = errCode;
+  return errCode;
+}
+
+static int32_t addNamespace(STranslateContext* pCxt, void* pTable) {
+  SArray* pTables = NULL;
+  if (taosArrayGetSize(pCxt->pNsLevel) > pCxt->currLevel) {
+    pTables = taosArrayGetP(pCxt->pNsLevel, pCxt->currLevel);
+  } else {
+    pTables = taosArrayInit(TARRAY_MIN_SIZE, POINTER_BYTES);
+  }
+  taosArrayPush(pTables, &pTable);
+  return TSDB_CODE_SUCCESS;
+}
+
+static SName* toName(const SRealTableNode* pRealTable, SName* pName) {
+  strncpy(pName->dbname, pRealTable->table.dbName, strlen(pRealTable->table.dbName));
+  strncpy(pName->dbname, pRealTable->table.tableName, strlen(pRealTable->table.tableName));
+  return pName;
+}
+
+static bool belongTable(const char* currentDb, const SColumnNode* pCol, const STableNode* pTable) {
+  int cmp = 0;
+  if ('\0' != pCol->dbName[0]) {
+    cmp = strcmp(pCol->dbName, pTable->dbName);
+  } else {
+    cmp = strcmp(currentDb, pTable->dbName);
+  }
+  if (0 == cmp) {
+    cmp = strcmp(pCol->tableAlias, pTable->tableAlias);
+  }
+  return (0 == cmp);
+}
+
+static SNodeList* getProjectList(SNode* pNode) {
+  if (QUERY_NODE_SELECT_STMT == nodeType(pNode)) {
+    return ((SSelectStmt*)pNode)->pProjectionList;
+  }
+  return NULL;
+}
+
+static int32_t createColumnNodeByTable(const STableNode* pTable, SNodeList* pList) {
+  if (QUERY_NODE_REAL_TABLE == nodeType(pTable)) {
+    const STableMeta* pMeta = ((SRealTableNode*)pTable)->pMeta;
+    int32_t nums = pMeta->tableInfo.numOfTags + pMeta->tableInfo.numOfColumns;
+    for (int32_t i = 0; i < nums; ++i) {
+      SColumnNode* pCol = (SColumnNode*)nodesMakeNode(QUERY_NODE_COLUMN);
+      pCol->colId = pMeta->schema[i].colId;
+      pCol->colType = pMeta->schema[i].type;
+      pCol->node.resType.bytes = pMeta->schema[i].bytes;
+      nodesListAppend(pList, (SNode*)pCol);
+    }
+  } else {
+    SNodeList* pProjectList = getProjectList(((STempTableNode*)pTable)->pSubquery);
+    SNode* pNode;
+    FOREACH(pNode, pProjectList) {
+      SExprNode* pExpr = (SExprNode*)pNode;
+      SColumnNode* pCol = (SColumnNode*)nodesMakeNode(QUERY_NODE_COLUMN);
+      pCol->pProjectRef = (SNode*)pExpr;
+      pExpr->pAssociationList = nodesListAppend(pExpr->pAssociationList, (SNode*)pCol);
+      pCol->node.resType = pExpr->resType;
+      nodesListAppend(pList, (SNode*)pCol);
+    }
+  }
+}
+
+static bool findAndSetColumn(SColumnNode* pCol, const STableNode* pTable) {
+  bool found = false;
+  if (QUERY_NODE_REAL_TABLE == nodeType(pTable)) {
+    const STableMeta* pMeta = ((SRealTableNode*)pTable)->pMeta;
+    int32_t nums = pMeta->tableInfo.numOfTags + pMeta->tableInfo.numOfColumns;
+    for (int32_t i = 0; i < nums; ++i) {
+      if (0 == strcmp(pCol->colName, pMeta->schema[i].name)) {
+        pCol->colId = pMeta->schema[i].colId;
+        pCol->colType = pMeta->schema[i].type;
+        pCol->node.resType.bytes = pMeta->schema[i].bytes;
+        found = true;
+        break;
+      }
+    }
+  } else {
+    SNodeList* pProjectList = getProjectList(((STempTableNode*)pTable)->pSubquery);
+    SNode* pNode;
+    FOREACH(pNode, pProjectList) {
+      SExprNode* pExpr = (SExprNode*)pNode;
+      if (0 == strcmp(pCol->colName, pExpr->aliasName)) {
+        pCol->pProjectRef = (SNode*)pExpr;
+        pExpr->pAssociationList = nodesListAppend(pExpr->pAssociationList, (SNode*)pCol);
+        pCol->node.resType = pExpr->resType;
+        found = true;
+        break;
+      }
+    }
+  }
+  return found;
+}
+
+static bool doTranslateExpr(SNode* pNode, void* pContext) {
+  STranslateContext* pCxt = (STranslateContext*)pContext;
+  switch (nodeType(pNode)) {
+    case QUERY_NODE_COLUMN: {
+      SColumnNode* pCol = (SColumnNode*)pNode;
+      SArray* pTables = taosArrayGetP(pCxt->pNsLevel, pCxt->currLevel);
+      size_t nums = taosArrayGetSize(pTables);
+      bool hasTableAlias = ('\0' != pCol->tableAlias[0]);
+      bool found = false;
+      for (size_t i = 0; i < nums; ++i) {
+        STableNode* pTable = taosArrayGetP(pTables, i);
+        if (hasTableAlias) {
+          if (belongTable(pCxt->pParseCxt->db, pCol, pTable)) {
+            if (findAndSetColumn(pCol, pTable)) {
+              break;
+            }
+            generateSyntaxErrMsg(pCxt, TSDB_CODE_PARSER_INVALID_COLUMN, pCol->colName);
+            return false;
+          }
+        } else {
+          if (findAndSetColumn(pCol, pTable)) {
+            if (found) {
+              generateSyntaxErrMsg(pCxt, TSDB_CODE_PARSER_AMBIGUOUS_COLUMN, pCol->colName);
+              return false;
+            }
+            found = true;
+          }
+        }
+      }
+      break;
+    }
+    case QUERY_NODE_VALUE:
+      break; // todo check literal format
+    case QUERY_NODE_OPERATOR: {
+
+      break;
+    }
+    case QUERY_NODE_FUNCTION:
+      break; // todo
+    case QUERY_NODE_TEMP_TABLE:
+      return translateSubquery(pCxt, ((STempTableNode*)pNode)->pSubquery);
+    default:
+      break;
+  }
+  return true;
+}
+
+static int32_t translateExpr(STranslateContext* pCxt, SNode* pNode) {
+  nodesWalkNodePostOrder(pNode, doTranslateExpr, pCxt);
+  return pCxt->errCode;
+}
+
+static int32_t translateExprList(STranslateContext* pCxt, SNodeList* pList) {
+  nodesWalkListPostOrder(pList, doTranslateExpr, pCxt);
+  return pCxt->errCode;
+}
+
+static int32_t translateTable(STranslateContext* pCxt, SNode* pTable) {
+  int32_t code = TSDB_CODE_SUCCESS;
+  switch (nodeType(pTable)) {
+    case QUERY_NODE_REAL_TABLE: {
+      SRealTableNode* pRealTable = (SRealTableNode*)pTable;
+      if ('\0' == pRealTable->table.dbName[0]) {
+        strcpy(pRealTable->table.dbName, pCxt->pParseCxt->db);
+      }
+      if ('\0' == pRealTable->table.tableAlias[0]) {
+        strcpy(pRealTable->table.tableAlias, pRealTable->table.tableName);
+      }
+      SName name;
+      code = catalogGetTableMeta(
+          pCxt->pParseCxt->pCatalog, pCxt->pParseCxt->pTransporter, &(pCxt->pParseCxt->mgmtEpSet), toName(pRealTable, &name), &(pRealTable->pMeta));
+      if (TSDB_CODE_SUCCESS != code) {
+        return generateSyntaxErrMsg(pCxt, TSDB_CODE_PARSER_TABLE_NOT_EXIST, pRealTable->table.tableName);
+      }
+      code = addNamespace(pCxt, pRealTable);
+      break;
+    }
+    case QUERY_NODE_TEMP_TABLE: {
+      STempTableNode* pTempTable = (STempTableNode*)pTable;
+      code = translateSubquery(pCxt, pTempTable->pSubquery);
+      if (TSDB_CODE_SUCCESS == code) {
+        code = addNamespace(pCxt, pTempTable);
+      }
+      break;
+    }
+    case QUERY_NODE_JOIN_TABLE: {
+      SJoinTableNode* pJoinTable = (SJoinTableNode*)pTable;
+      code = translateTable(pCxt, pJoinTable->pLeft);
+      if (TSDB_CODE_SUCCESS == code) {
+        code = translateTable(pCxt, pJoinTable->pRight);
+      }
+      if (TSDB_CODE_SUCCESS == code) {
+        code = translateExpr(pCxt, pJoinTable->pOnCond);
+      }
+      break;
+    }
+    default:
+      break;
+  }
+  return code;
+}
+
+static int32_t translateStar(STranslateContext* pCxt, SSelectStmt* pSelect, bool* pIsSelectStar) {
+  if (NULL == pSelect->pProjectionList) { // select * ...
+    SArray* pTables = taosArrayGetP(pCxt->pNsLevel, pCxt->currLevel);
+    size_t nums = taosArrayGetSize(pTables);
+    for (size_t i = 0; i < nums; ++i) {
+      STableNode* pTable = taosArrayGetP(pTables, i);
+      createColumnNodeByTable(pTable, pSelect->pProjectionList);
+    }
+    *pIsSelectStar = true;
+  } else {
+
+  }
+}
+
+static int32_t translateSelect(STranslateContext* pCxt, SSelectStmt* pSelect) {
+  int32_t code = TSDB_CODE_SUCCESS;
+  code = translateTable(pCxt, pSelect->pFromTable);
+  if (TSDB_CODE_SUCCESS == code) {
+    code = translateExpr(pCxt, pSelect->pWhere);
+  }
+  bool isSelectStar = false;
+  if (TSDB_CODE_SUCCESS == code) {
+    code = translateStar(pCxt, pSelect, &isSelectStar);
+  }
+  if (TSDB_CODE_SUCCESS == code && !isSelectStar) {
+    code = translateExprList(pCxt, pSelect->pProjectionList);
+  }
+  return code;
+}
+
+static int32_t translateQuery(STranslateContext* pCxt, SNode* pNode) {
+  int32_t code = TSDB_CODE_SUCCESS;
+  switch (nodeType(pNode)) {
+    case QUERY_NODE_SELECT_STMT:
+      code = translateSelect(pCxt, (SSelectStmt*)pNode);
+      break;
+    default:
+      break;
+  }
+  return code;
+}
+
+static int32_t translateSubquery(STranslateContext* pCxt, SNode* pNode) {
+  ++(pCxt->currLevel);
+  int32_t code = translateQuery(pCxt, pNode);
+  --(pCxt->currLevel);
+  return code;
+}
+
+int32_t doTranslate(SParseContext* pParseCxt, SQuery* pQuery) {
+  STranslateContext cxt = { .pParseCxt = pParseCxt, .pNsLevel = taosArrayInit(TARRAY_MIN_SIZE, POINTER_BYTES), .currLevel = 0 };
+  return translateQuery(&cxt, pQuery->pRoot);
+}

source/libs/parser/test/newParserTest.cpp

@@ -71,8 +71,8 @@ private:
     switch (nodeType(node)) {
       case QUERY_NODE_REAL_TABLE: {
         SRealTableNode* realTable = (SRealTableNode*)table;
-        if ('\0' != realTable->dbName[0]) {
-          sql.append(realTable->dbName);
+        if ('\0' != realTable->table.dbName[0]) {
+          sql.append(realTable->table.dbName);
           sql.append(".");
         }
         sql.append(realTable->table.tableName);

source/nodes/src/nodesTraverseFuncs.c

@@ -15,68 +15,101 @@
 
 #include "nodes.h"
 
-typedef bool (*FQueryNodeWalker)(SNode* pNode, void* pContext);
+typedef enum ETraversalOrder {
+  TRAVERSAL_PREORDER = 1,
+  TRAVERSAL_POSTORDER
+} ETraversalOrder;
 
-bool nodesWalkNodeList(SNodeList* pNodeList, FQueryNodeWalker walker, void* pContext) {
-  SNode* node;
-  FOREACH(node, pNodeList) {
-    if (!nodesWalkNode(node, walker, pContext)) {
-      return false;
-    }
-  }
-  return true;
-}
+static bool walkList(SNodeList* pNodeList, ETraversalOrder order, FQueryNodeWalker walker, void* pContext);
 
-bool nodesWalkNode(SNode* pNode, FQueryNodeWalker walker, void* pContext) {
+static bool walkNode(SNode* pNode, ETraversalOrder order, FQueryNodeWalker walker, void* pContext) {
   if (NULL == pNode) {
     return true;
   }
 
-  if (!walker(pNode, pContext)) {
+  if (TRAVERSAL_PREORDER == order && !walker(pNode, pContext)) {
     return false;
   }
 
+  bool res = true;
   switch (nodeType(pNode)) {
     case QUERY_NODE_COLUMN:
     case QUERY_NODE_VALUE:
     case QUERY_NODE_LIMIT:
       // these node types with no subnodes
-      return true;
+      break;
     case QUERY_NODE_OPERATOR: {
       SOperatorNode* pOpNode = (SOperatorNode*)pNode;
-      if (!nodesWalkNode(pOpNode->pLeft, walker, pContext)) {
-        return false;
+      res = walkNode(pOpNode->pLeft, order, walker, pContext);
+      if (res) {
+        res = walkNode(pOpNode->pRight, order, walker, pContext);
       }
-      return nodesWalkNode(pOpNode->pRight, walker, pContext);
+      break;
     }
     case QUERY_NODE_LOGIC_CONDITION:
-      return nodesWalkNodeList(((SLogicConditionNode*)pNode)->pParameterList, walker, pContext);
+      res = walkList(((SLogicConditionNode*)pNode)->pParameterList, order, walker, pContext);
+      break;
     case QUERY_NODE_IS_NULL_CONDITION:
-      return nodesWalkNode(((SIsNullCondNode*)pNode)->pExpr, walker, pContext);
+      res = walkNode(((SIsNullCondNode*)pNode)->pExpr, order, walker, pContext);
+      break;
     case QUERY_NODE_FUNCTION:
-      return nodesWalkNodeList(((SFunctionNode*)pNode)->pParameterList, walker, pContext);
+      res = walkList(((SFunctionNode*)pNode)->pParameterList, order, walker, pContext);
+      break;
     case QUERY_NODE_REAL_TABLE:
     case QUERY_NODE_TEMP_TABLE:
-      return true; // todo
+      break; // todo
     case QUERY_NODE_JOIN_TABLE: {
       SJoinTableNode* pJoinTableNode = (SJoinTableNode*)pNode;
-      if (!nodesWalkNode(pJoinTableNode->pLeft, walker, pContext)) {
-        return false;
+      res = walkNode(pJoinTableNode->pLeft, order, walker, pContext);
+      if (res) {
+        res = walkNode(pJoinTableNode->pRight, order, walker, pContext);
       }
-      if (!nodesWalkNode(pJoinTableNode->pRight, walker, pContext)) {
-        return false;
+      if (res) {
+        res = walkNode(pJoinTableNode->pOnCond, order, walker, pContext);
       }
-      return nodesWalkNode(pJoinTableNode->pOnCond, walker, pContext);
+      break;
     }
     case QUERY_NODE_GROUPING_SET:
-      return nodesWalkNodeList(((SGroupingSetNode*)pNode)->pParameterList, walker, pContext);
+      res = walkList(((SGroupingSetNode*)pNode)->pParameterList, order, walker, pContext);
+      break;
     case QUERY_NODE_ORDER_BY_EXPR:
-      return nodesWalkNode(((SOrderByExprNode*)pNode)->pExpr, walker, pContext);
+      res = walkNode(((SOrderByExprNode*)pNode)->pExpr, order, walker, pContext);
+      break;
     default:
       break;
   }
 
-  return false;
+  if (res && TRAVERSAL_POSTORDER == order) {
+    res = walker(pNode, pContext);
+  }
+
+  return res;
+}
+
+static bool walkList(SNodeList* pNodeList, ETraversalOrder order, FQueryNodeWalker walker, void* pContext) {
+  SNode* node;
+  FOREACH(node, pNodeList) {
+    if (!walkNode(node, order, walker, pContext)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+void nodesWalkNode(SNode* pNode, FQueryNodeWalker walker, void* pContext) {
+  (void)walkNode(pNode, TRAVERSAL_PREORDER, walker, pContext);
+}
+
+void nodesWalkList(SNodeList* pNodeList, FQueryNodeWalker walker, void* pContext) {
+  (void)walkList(pNodeList, TRAVERSAL_PREORDER, walker, pContext);
+}
+
+void nodesWalkNodePostOrder(SNode* pNode, FQueryNodeWalker walker, void* pContext) {
+  (void)walkNode(pNode, TRAVERSAL_POSTORDER, walker, pContext);
+}
+
+void nodesWalkListPostOrder(SNodeList* pList, FQueryNodeWalker walker, void* pContext) {
+  (void)walkList(pList, TRAVERSAL_PREORDER, walker, pContext);
 }
 
 bool nodesWalkStmt(SNode* pNode, FQueryNodeWalker walker, void* pContext) {