[td-225] fix error in top/bottom query

src/client/src/tscFunctionImpl.c

@@ -2292,8 +2292,9 @@ static void top_func_second_merge(SQLFunctionCtx *pCtx) {
   
   // the intermediate result is binary, we only use the output data type
   for (int32_t i = 0; i < pInput->num; ++i) {
+    int16_t type = (pCtx->outputType == TSDB_DATA_TYPE_FLOAT)? TSDB_DATA_TYPE_DOUBLE:pCtx->outputType;
     do_top_function_add(pOutput, pCtx->param[0].i64Key, &pInput->res[i]->v.i64Key, pInput->res[i]->timestamp,
-                        pCtx->outputType, &pCtx->tagInfo, pInput->res[i]->pTags, pCtx->currentStage);
+                        type, &pCtx->tagInfo, pInput->res[i]->pTags, pCtx->currentStage);
   }
   
   SET_VAL(pCtx, pInput->num, pOutput->num);