diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c
index 699a050aea7084fd92559d23db7be6c7c97f516b..a6fa8ea72126d272c8a4113780f98ce1e153ec60 100644
--- a/source/libs/function/src/builtins.c
+++ b/source/libs/function/src/builtins.c
@@ -1890,7 +1890,7 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
   {
     .name = "first",
     .type = FUNCTION_TYPE_FIRST,
-    .classification = FUNC_MGT_AGG_FUNC | FUNC_MGT_MULTI_RES_FUNC | FUNC_MGT_TIMELINE_FUNC,
+    .classification = FUNC_MGT_AGG_FUNC | FUNC_MGT_SELECT_FUNC | FUNC_MGT_MULTI_RES_FUNC | FUNC_MGT_TIMELINE_FUNC,
     .translateFunc = translateFirstLast,
     .getEnvFunc   = getFirstLastFuncEnv,
     .initFunc     = functionSetup,
@@ -1903,7 +1903,7 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
   {
     .name = "_first_partial",
     .type = FUNCTION_TYPE_FIRST_PARTIAL,
-    .classification = FUNC_MGT_AGG_FUNC | FUNC_MGT_MULTI_RES_FUNC | FUNC_MGT_TIMELINE_FUNC,
+    .classification = FUNC_MGT_AGG_FUNC | FUNC_MGT_SELECT_FUNC | FUNC_MGT_MULTI_RES_FUNC | FUNC_MGT_TIMELINE_FUNC,
     .translateFunc = translateFirstLastPartial,
     .getEnvFunc   = getFirstLastFuncEnv,
     .initFunc     = functionSetup,
diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c
index 06f24f39e75eaca29a3ca75fc2f698bb0773b83f..d5e5b385580854e528fa8c1d356e46dc3d718d1e 100644
--- a/source/libs/function/src/builtinsimpl.c
+++ b/source/libs/function/src/builtinsimpl.c
@@ -2413,7 +2413,7 @@ int32_t getFirstLastInfoSize(int32_t resBytes) { return sizeof(SFirstLastRes) +
 
 bool getFirstLastFuncEnv(SFunctionNode* pFunc, SFuncExecEnv* pEnv) {
   SColumnNode* pNode = (SColumnNode*)nodesListGetNode(pFunc->pParameterList, 0);
-  pEnv->calcMemSize = sizeof(SFirstLastRes) + pNode->node.resType.bytes + sizeof(int64_t);
+  pEnv->calcMemSize = sizeof(SFirstLastRes) + pNode->node.resType.bytes + sizeof(int64_t) + sizeof(STuplePos);
   return true;
 }
 
@@ -2491,9 +2491,15 @@ int32_t firstFunction(SqlFunctionCtx* pCtx) {
         }
         memcpy(pInfo->buf, data, bytes);
         *(TSKEY*)(pInfo->buf + bytes) = cts;
-        pInfo->hasResult = true;
-        //        DO_UPDATE_TAG_COLUMNS(pCtx, ts);
-
+        //handle selectivity
+        STuplePos* pTuplePos = (STuplePos*)(pInfo->buf + bytes + sizeof(TSKEY));
+        if (!pInfo->hasResult) {
+          saveTupleData(pCtx, i, pCtx->pSrcBlock, pTuplePos);
+          pInfo->hasResult = true;
+        } else {
+          copyTupleData(pCtx, i, pCtx->pSrcBlock, pTuplePos);
+        }
+        //DO_UPDATE_TAG_COLUMNS(pCtx, ts);
         pResInfo->numOfRes = 1;
         break;
       }
@@ -2525,8 +2531,15 @@ int32_t firstFunction(SqlFunctionCtx* pCtx) {
         }
         memcpy(pInfo->buf, data, bytes);
         *(TSKEY*)(pInfo->buf + bytes) = cts;
-        pInfo->hasResult = true;
-        //        DO_UPDATE_TAG_COLUMNS(pCtx, ts);
+        //handle selectivity
+        STuplePos* pTuplePos = (STuplePos*)(pInfo->buf + bytes + sizeof(TSKEY));
+        if (!pInfo->hasResult) {
+          saveTupleData(pCtx, i, pCtx->pSrcBlock, pTuplePos);
+          pInfo->hasResult = true;
+        } else {
+          copyTupleData(pCtx, i, pCtx->pSrcBlock, pTuplePos);
+        }
+        //DO_UPDATE_TAG_COLUMNS(pCtx, ts);
         pResInfo->numOfRes = 1;
         break;
       }
@@ -2669,6 +2682,8 @@ int32_t firstLastFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock) {
 
   SFirstLastRes* pRes = GET_ROWCELL_INTERBUF(pResInfo);
   colDataAppend(pCol, pBlock->info.rows, pRes->buf, pResInfo->isNullRes);
+  STuplePos* pTuplePos = (STuplePos*)(pRes->buf + pRes->bytes + sizeof(TSKEY));
+  setSelectivityValue(pCtx, pBlock, pTuplePos, pBlock->info.rows);
 
   return pResInfo->numOfRes;
 }