From a80027736dea7606ae29ce6fee25873e4b58dbf4 Mon Sep 17 00:00:00 2001
From: Ganlin Zhao <ganlinzhao@hotmail.com>
Date: Mon, 18 Jul 2022 14:47:53 +0800
Subject: [PATCH] feat(query): add top/bottom function scalar version

---
 include/libs/scalar/scalar.h        |  2 ++
 source/libs/function/src/builtins.c |  2 ++
 source/libs/scalar/src/sclfunc.c    | 29 +++++++++++++++++++++++++++++
 3 files changed, 33 insertions(+)

diff --git a/include/libs/scalar/scalar.h b/include/libs/scalar/scalar.h
index 1f20a64314..b667207684 100644
--- a/include/libs/scalar/scalar.h
+++ b/include/libs/scalar/scalar.h
@@ -117,6 +117,8 @@ int32_t diffScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam
 int32_t stateCountScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOutput);
 int32_t stateDurationScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOutput);
 int32_t histogramScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOutput);
+int32_t topScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOutput);
+int32_t bottomScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOutput);
 
 #ifdef __cplusplus
 }
diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c
index 72eabafa16..b6a351b4a6 100644
--- a/source/libs/function/src/builtins.c
+++ b/source/libs/function/src/builtins.c
@@ -2086,6 +2086,7 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
     .getEnvFunc   = getTopBotFuncEnv,
     .initFunc     = topBotFunctionSetup,
     .processFunc  = topFunction,
+    .sprocessFunc = topScalarFunction,
     .finalizeFunc = topBotFinalize,
     .combineFunc  = topCombine,
     .pPartialFunc = "top",
@@ -2100,6 +2101,7 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
     .getEnvFunc   = getTopBotFuncEnv,
     .initFunc     = topBotFunctionSetup,
     .processFunc  = bottomFunction,
+    .sprocessFunc = bottomScalarFunction,
     .finalizeFunc = topBotFinalize,
     .combineFunc  = bottomCombine,
     .pPartialFunc = "bottom",
diff --git a/source/libs/scalar/src/sclfunc.c b/source/libs/scalar/src/sclfunc.c
index cadeaa0164..1cbaf9690e 100644
--- a/source/libs/scalar/src/sclfunc.c
+++ b/source/libs/scalar/src/sclfunc.c
@@ -2816,3 +2816,32 @@ int32_t histogramScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarP
   pOutput->numOfRows = numOfBins;
   return TSDB_CODE_SUCCESS;
 }
+
+int32_t selectScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOutput) {
+  SColumnInfoData *pInputData  = pInput->columnData;
+  SColumnInfoData *pOutputData = pOutput->columnData;
+
+  int32_t type = GET_PARAM_TYPE(pInput);
+
+  for (int32_t i = 0; i < pInput->numOfRows; ++i) {
+    if (colDataIsNull_s(pInputData, i)) {
+      colDataAppendNULL(pOutputData, 0);
+      continue;
+    }
+
+    char* data = colDataGetData(pInputData, i);
+    colDataAppend(pOutputData, i, data, false);
+  }
+
+
+  pOutput->numOfRows = 1;
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t topScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOutput) {
+  return selectScalarFunction(pInput, inputNum, pOutput);
+}
+
+int32_t bottomScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOutput) {
+  return selectScalarFunction(pInput, inputNum, pOutput);
+}