Merge pull request #22725 from taosdata/fix/TS-3895

fix: fix last(*)/last_row(*) return MD5 hashed column name

source/libs/parser/src/parTranslater.c

@@ -2902,7 +2902,7 @@ static SNode* createMultiResFunc(SFunctionNode* pSrcFunc, SExprNode* pExpr) {
       taosCreateMD5Hash(buf, len);
       strncpy(pFunc->node.aliasName, buf, TSDB_COL_NAME_LEN  - 1);
       len = snprintf(buf, sizeof(buf) - 1, "%s(%s)", pSrcFunc->functionName, pCol->colName);
-      taosCreateMD5Hash(buf, len);
+      // note: userAlias could be truncated here
       strncpy(pFunc->node.userAlias, buf, TSDB_COL_NAME_LEN - 1);
     }
   } else {
@@ -2910,7 +2910,7 @@ static SNode* createMultiResFunc(SFunctionNode* pSrcFunc, SExprNode* pExpr) {
     taosCreateMD5Hash(buf, len);
     strncpy(pFunc->node.aliasName, buf, TSDB_COL_NAME_LEN - 1);
     len = snprintf(buf, sizeof(buf) - 1, "%s(%s)", pSrcFunc->functionName, pExpr->userAlias);
-    taosCreateMD5Hash(buf, len);
+    // note: userAlias could be truncated here
     strncpy(pFunc->node.userAlias, buf, TSDB_COL_NAME_LEN - 1);
   }
 

tests/script/tsim/query/multires_func.sim

+system sh/stop_dnodes.sh
+system sh/deploy.sh -n dnode1 -i 1
+system sh/exec.sh -n dnode1 -s start
+sql connect
+
+sql create database test
+sql use test
+sql CREATE TABLE `tb` (`ts` TIMESTAMP, `c0` INT, `c1` FLOAT, `c2` BINARY(10))
+
+
+sql insert into tb values("2022-05-15 00:01:08.000", 1, 1.0, "abc")
+sql insert into tb values("2022-05-16 00:01:08.000", 2, 2.0, "bcd")
+sql insert into tb values("2022-05-17 00:01:08.000", 3, 3.0, "cde")
+
+
+#sleep 10000000
+system taos -P7100 -s 'source tsim/query/t/multires_func.sql' | grep -v 'Query OK' | grep -v 'Client Version' > /tmp/multires_func.result
+system echo ----------------------diff start-----------------------
+system git diff --exit-code --color tsim/query/r/multires_func.result /tmp/multires_func.result
+system echo ----------------------diff succeed-----------------------

tests/script/tsim/query/r/multires_func.result

+Copyright (c) 2022 by TDengine, all rights reserved.
+
+taos> source tsim/query/t/multires_func.sql
+taos> use test;
+Database changed.
+
+taos> select count(*) from tb\G;
+*************************** 1.row ***************************
+count(*): 3
+
+taos> select last(*) from tb\G;
+*************************** 1.row ***************************
+ts: 2022-05-17 00:01:08.000
+c0: 3
+c1: 3.0000000
+c2: cde
+
+taos> select last_row(*) from tb\G;
+*************************** 1.row ***************************
+ts: 2022-05-17 00:01:08.000
+c0: 3
+c1: 3.0000000
+c2: cde
+
+taos> select first(*) from tb\G;
+*************************** 1.row ***************************
+ts: 2022-05-15 00:01:08.000
+c0: 1
+c1: 1.0000000
+c2: abc
+

tests/script/tsim/query/t/multires_func.sql

+use test;
+select count(*) from tb\G;
+select last(*) from tb\G;
+select last_row(*) from tb\G;
+select first(*) from tb\G;