feat(query): add mavg function

source/libs/function/src/builtinsimpl.c

@@ -3013,7 +3013,6 @@ int32_t mavgFunction(SqlFunctionCtx* pCtx) {
       } else {
         pInfo->sum = pInfo->sum + v - pInfo->points[pInfo->pos];
       }
-    }
 
       pInfo->points[pInfo->pos] = v;
       double result = pInfo->sum / pInfo->numOfPoints;
@@ -3023,9 +3022,14 @@ int32_t mavgFunction(SqlFunctionCtx* pCtx) {
       if (pTsOutput != NULL) {
         colDataAppendInt64(pTsOutput, pos, &tsList[i]);
       }
-
       numOfElems++;
     }
 
+    pInfo->pos++;
+    if (pInfo->pos == pInfo->numOfPoints) {
+      pInfo->pos = 0;
+    }
+  }
+
   return numOfElems;
 }