B库下insert、upsert的用户变量与列名相同时，取用户变量优先级最高，与MySQL保持一致

src/common/backend/parser/parse_expr.cpp

@@ -966,10 +966,15 @@ Node* transformColumnRef(ParseState* pstate, ColumnRef* cref)
         if (node == NULL) {
             node = hookresult;
         } else if (hookresult != NULL) {
-            ereport(ERROR,
-                (errcode(ERRCODE_AMBIGUOUS_COLUMN),
-                    errmsg("column reference \"%s\" is ambiguous", NameListToString(cref->fields)),
-                    parser_errposition(pstate, cref->location)));
+            if (IS_SUPPORT_RIGHT_REF(pstate->rightRefState)) {
+                node = hookresult;
+            } else {
+                ereport(ERROR,
+                    (errcode(ERRCODE_AMBIGUOUS_COLUMN),
+                        errmsg("column reference \"%s\" is ambiguous", NameListToString(cref->fields)),
+                        parser_errposition(pstate, cref->location)));
+            }
+
         }
     }
     

src/common/pl/plpgsql/src/pl_comp.cpp

@@ -1621,7 +1621,7 @@ static Node* plpgsql_post_column_ref(ParseState* pstate, ColumnRef* cref, Node*
      */
     Node* myvar = resolve_column_ref(pstate, expr, cref, (var == NULL));
 
-    if (myvar != NULL && var != NULL) {
+    if (myvar != NULL && var != NULL && !IS_SUPPORT_RIGHT_REF(pstate->rightRefState)) {
         /*
          * We could leave it to the core parser to throw this error, but we
          * can add a more useful detail message than the core could.

src/test/regress/expected/insert_right_ref.out

@@ -148,5 +148,29 @@ select * from upser order by c1;
 (15 rows)
 
 drop table upser;
+-- test var
+create table with_var(a int default 999);
+create function with_var_func() return int as
+declare 
+    a int := 666;
+begin
+    insert into with_var values(a);
+    return a;
+end;
+/
+call with_var_func();
+ with_var_func 
+---------------
+           666
+(1 row)
+
+select * from with_var;
+  a  
+-----
+ 666
+(1 row)
+
+drop function with_var_func;
+drop table with_var;
 \c postgres
 drop database rightref;

src/test/regress/sql/insert_right_ref.sql

@@ -65,6 +65,23 @@ select * from upser order by c1;
 
 drop table upser;
 
+-- test var
+create table with_var(a int default 999);
+create function with_var_func() return int as
+declare 
+    a int := 666;
+begin
+    insert into with_var values(a);
+    return a;
+end;
+/
+
+call with_var_func();
+select * from with_var;
+
+drop function with_var_func;
+drop table with_var;
+
 \c postgres
 
 drop database rightref;