Changed alias handling in CBO (#15311)

Co-authored-by: Pavel Velikhov <[email protected]>

Author: pavelvelikhov

ydb/library/yql/dq/opt/dq_opt_join_hypergraph.h

@@ -54,13 +54,13 @@ class TJoinHypergraph {
 
         void RemoveAttributeAliases() {
             for (auto& leftKey : LeftJoinKeys) {
-                if (auto idx = leftKey.AttributeName.find_last_of('.'); idx != TString::npos) {
+                if (auto idx = leftKey.AttributeName.find('.'); idx != TString::npos) {
                     leftKey.AttributeName = leftKey.AttributeName.substr(idx + 1);
                 }
             }
 
             for (auto& rightKey : RightJoinKeys) {
-                if (auto idx = rightKey.AttributeName.find_last_of('.'); idx != TString::npos) {
+                if (auto idx = rightKey.AttributeName.find('.'); idx != TString::npos) {
                     rightKey.AttributeName = rightKey.AttributeName.substr(idx + 1);
                 }
             }

ydb/library/yql/dq/opt/dq_opt_stat.cpp

@@ -24,16 +24,16 @@ namespace {
 
 
     TString RemoveAliases(TString attributeName) {
-        if (auto idx = attributeName.find_last_of('.'); idx != TString::npos) {
+        if (auto idx = attributeName.find('.'); idx != TString::npos) {
             return attributeName.substr(idx+1);
         }
         return attributeName;
     }
 
     TString ExtractAlias(TString attributeName) {
-        if (auto idx = attributeName.find_last_of('.'); idx != TString::npos) {
+        if (auto idx = attributeName.find('.'); idx != TString::npos) {
             auto substr = attributeName.substr(0, idx);
-            if (auto idx2 = substr.find_last_of('.'); idx != TString::npos) {
+            if (auto idx2 = substr.find('.'); idx != TString::npos) {
                 substr = substr.substr(idx2+1);
             }
             return substr;