[TD-11216]<feature>: Time window related keywords

src/client/src/tscSQLParser.c

@@ -2516,20 +2516,7 @@ int32_t addProjectionExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, t
             return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg7);
           }
           colSchema  = *tGetTimeWindowColumnSchema(index.columnIndex);
-          switch (index.columnIndex) {
-            case TSDB_TSWIN_START_COLUMN_INDEX: {
-              functionId = TSDB_FUNC_WSTART;
-              break;
-            }
-            case TSDB_TSWIN_STOP_COLUMN_INDEX: {
-              functionId = TSDB_FUNC_WSTOP;
-              break;
-            }
-            case TSDB_TSWIN_DURATION_COLUMN_INDEX: {
-              functionId = TSDB_FUNC_WDURATION;
-              break;
-            }
-          }
+          functionId = getTimeWindowFunctionID(index.columnIndex);
           colType    = TSDB_COL_NORMAL;
         }
         char name[TSDB_COL_NAME_LEN] = {0};

src/query/inc/qAggMain.h

@@ -233,6 +233,8 @@ int32_t getResultDataInfo(int32_t dataType, int32_t dataBytes, int32_t functionI
                           int32_t *len, int32_t *interBytes, int16_t extLength, bool isSuperTable, SUdfInfo* pUdfInfo);
 int32_t isValidFunction(const char* name, int32_t len);
 
+int16_t getTimeWindowFunctionID(int16_t colIndex);
+
 #define IS_STREAM_QUERY_VALID(x)  (((x)&TSDB_FUNCSTATE_STREAM) != 0)
 #define IS_MULTIOUTPUT(x)         (((x)&TSDB_FUNCSTATE_MO) != 0)
 #define IS_SINGLEOUTPUT(x)        (((x)&TSDB_FUNCSTATE_SO) != 0)

src/query/src/qAggMain.c

@@ -5627,6 +5627,22 @@ static void tail_func_finalizer(SQLFunctionCtx *pCtx) {
   doFinalizer(pCtx);
 }
 
+int16_t getTimeWindowFunctionID(int16_t colIndex) {
+  switch (colIndex) {
+    case TSDB_TSWIN_START_COLUMN_INDEX: {
+      return TSDB_FUNC_WSTART;
+    }
+    case TSDB_TSWIN_STOP_COLUMN_INDEX: {
+      return TSDB_FUNC_WSTOP;
+    }
+    case TSDB_TSWIN_DURATION_COLUMN_INDEX: {
+      return TSDB_FUNC_WDURATION;
+    }
+    default:
+      return TSDB_FUNC_INVALID_ID;
+  }
+}
+
 static void wstart_function(SQLFunctionCtx *pCtx) {
   SET_VAL(pCtx, pCtx->size, 1);
   *(int64_t *)(pCtx->pOutput) = pCtx->startTs;