diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c
index f1b46aa69b4ce21616e696be702335a579927da4..1ed6dcad395c56406261c6fe21ed0fdb2efc6cf5 100644
--- a/source/libs/function/src/builtins.c
+++ b/source/libs/function/src/builtins.c
@@ -1976,7 +1976,7 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
   {
     .name = "leastsquares",
     .type = FUNCTION_TYPE_LEASTSQUARES,
-    .classification = FUNC_MGT_AGG_FUNC | FUNC_MGT_FORBID_STREAM_FUNC,
+    .classification = FUNC_MGT_AGG_FUNC | FUNC_MGT_TIMELINE_FUNC | FUNC_MGT_FORBID_STREAM_FUNC,
     .translateFunc = translateLeastSQR,
     .getEnvFunc   = getLeastSQRFuncEnv,
     .initFunc     = leastSQRFunctionSetup,
diff --git a/source/libs/parser/src/parCalcConst.c b/source/libs/parser/src/parCalcConst.c
index 4dff42592a56a5233a3ad6db5dad71a72c0e3e57..b799ae5fb1aa0a3c2602e9139b39cc42610dce05 100644
--- a/source/libs/parser/src/parCalcConst.c
+++ b/source/libs/parser/src/parCalcConst.c
@@ -218,7 +218,7 @@ static SNode* createConstantValue() {
 static int32_t calcConstProjections(SCalcConstContext* pCxt, SSelectStmt* pSelect, bool subquery) {
   SNode* pProj = NULL;
   WHERE_EACH(pProj, pSelect->pProjectionList) {
-    if (subquery && isUselessCol((SExprNode*)pProj)) {
+    if (subquery && !pSelect->isDistinct && isUselessCol((SExprNode*)pProj)) {
       ERASE_NODE(pSelect->pProjectionList);
       continue;
     }
diff --git a/source/libs/parser/src/parTranslater.c b/source/libs/parser/src/parTranslater.c
index da393bb883f6ed32fd425b96dbc7824c4b92df72..ca000fcf2d381d502f55a413d61d3906c802a06f 100644
--- a/source/libs/parser/src/parTranslater.c
+++ b/source/libs/parser/src/parTranslater.c
@@ -4757,8 +4757,13 @@ static int32_t extractQueryResultSchema(const SNodeList* pProjections, int32_t*
   int32_t index = 0;
   FOREACH(pNode, pProjections) {
     SExprNode* pExpr = (SExprNode*)pNode;
-    (*pSchema)[index].type = pExpr->resType.type;
-    (*pSchema)[index].bytes = pExpr->resType.bytes;
+    if (TSDB_DATA_TYPE_NULL == pExpr->resType.type) {
+      (*pSchema)[index].type = TSDB_DATA_TYPE_VARCHAR;
+      (*pSchema)[index].bytes = 0;
+    } else {
+      (*pSchema)[index].type = pExpr->resType.type;
+      (*pSchema)[index].bytes = pExpr->resType.bytes;
+    }
     (*pSchema)[index].colId = index + 1;
     if ('\0' != pExpr->userAlias[0]) {
       strcpy((*pSchema)[index].name, pExpr->userAlias);