MDEV-18943: Group Concat with limit not working with views

Adjusted the Item_func_group_concat::print function to take into account
limit if present with GROUP_CONCAT

Author: Varun Gupta

mysql-test/main/func_gconcat.result

@@ -1378,5 +1378,19 @@ group_concat(a,b limit ?)
 1a,1b,2x,2y
 drop table t2;
 #
+# MDEV-18943: Group Concat with limit not working with views
+#
+create table t1 (a int, b varchar(10));
+insert into t1 values(1,'a'),(1,'b'),(NULL,'c'),(2,'x'),(2,'y');
+select group_concat(a,b limit 2) from t1;
+group_concat(a,b limit 2)
+1a,1b
+create view v1 as select group_concat(a,b limit 2) from t1;
+select * from v1;
+group_concat(a,b limit 2)
+1a,1b
+drop view v1;
+drop table t1;
+#
 # End of 10.3 tests
 #

mysql-test/main/func_gconcat.test

@@ -985,6 +985,18 @@ prepare STMT from 'select group_concat(a,b limit ?) from t2';
 execute STMT using @x;
 drop table t2;
 
+--echo #
+--echo # MDEV-18943: Group Concat with limit not working with views
+--echo #
+
+create table t1 (a int, b varchar(10));
+insert into t1 values(1,'a'),(1,'b'),(NULL,'c'),(2,'x'),(2,'y');
+select group_concat(a,b limit 2) from t1;
+create view v1 as select group_concat(a,b limit 2) from t1;
+select * from v1;
+drop view v1;
+drop table t1;
+
 --echo #
 --echo # End of 10.3 tests
 --echo #

sql/item_sum.cc

@@ -4172,7 +4172,19 @@ void Item_func_group_concat::print(String *str, enum_query_type query_type)
   }
   str->append(STRING_WITH_LEN(" separator \'"));
   str->append_for_single_quote(separator->ptr(), separator->length());
-  str->append(STRING_WITH_LEN("\')"));
+  str->append(STRING_WITH_LEN("\'"));
+
+  if (limit_clause)
+  {
+    str->append(STRING_WITH_LEN(" limit "));
+    if (offset_limit)
+    {
+      offset_limit->print(str, query_type);
+      str->append(',');
+    }
+    row_limit->print(str, query_type);
+  }
+  str->append(STRING_WITH_LEN(")"));
 }