!6623 解决A模式下使用union all创建视图 varchar类型字段在视图中未显示字符串长度的问题

Merge pull request !6623 from yanguotao/view_a_compatibility

src/common/backend/parser/analyze.cpp

@@ -4097,6 +4097,10 @@ static Node* transformSetOperationTree(ParseState* pstate, SelectStmt* stmt, boo
             /* if same type and same typmod, use typmod; else default */
             if (lcoltype == rcoltype && lcoltypmod == rcoltypmod) {
                 rescoltypmod = lcoltypmod;
+            } else if (u_sess->attr.attr_sql.sql_compatibility == A_FORMAT && lcoltype == rcoltype && \
+                    !(lcoltypmod == -1 || rcoltypmod == -1)) {
+                /* same type, neither typmod is -1, select max */
+                rescoltypmod = Max(lcoltypmod, rcoltypmod);
             } else {
                 rescoltypmod = -1;
             }

src/test/regress/expected/create_view1.out

@@ -114,3 +114,25 @@ select relname from pg_class where relname = 'ttv1';
 reset restrict_nonsystem_relation_kind;
 drop view ttv1;
 drop table t1;
+create table tt3 (c1 varchar2(10),c2 varchar2(5));
+\d tt3;
+             Table "public.tt3"
+ Column |         Type          | Modifiers 
+--------+-----------------------+-----------
+ c1     | character varying(10) | 
+ c2     | character varying(5)  | 
+
+create table tt_union(col1 varchar2(15));
+insert into tt_union values('1234567890abcdr');
+create view t_v3 as select c1 as id from tt3 union all select col1 from tt_union;
+\d t_v3;
+             View "public.t_v3"
+ Column |         Type          | Modifiers 
+--------+-----------------------+-----------
+ id     | character varying(15) | 
+
+drop table tt3 cascade;
+NOTICE:  drop cascades to view t_v3
+drop view t_v3 cascade;
+ERROR:  view "t_v3" does not exist
+drop table tt_union cascade;

src/test/regress/sql/create_view1.sql

@@ -93,3 +93,13 @@ select relname from pg_class where relname = 'ttv1';
 reset restrict_nonsystem_relation_kind;
 drop view ttv1;
 drop table t1;
+
+create table tt3 (c1 varchar2(10),c2 varchar2(5));
+\d tt3;
+create table tt_union(col1 varchar2(15));
+insert into tt_union values('1234567890abcdr');
+create view t_v3 as select c1 as id from tt3 union all select col1 from tt_union;
+\d t_v3;
+drop table tt3 cascade;
+drop view t_v3 cascade;
+drop table tt_union cascade;