MDEV-14787 CREATE does not allow tables with versioning columns only, but ALTER does

mysql-test/suite/versioning/r/alter.result

@@ -445,5 +445,10 @@ t	CREATE TABLE `t` (
 alter table t add fulltext key (c);
 Warnings:
 Warning	124	InnoDB rebuilding table to add column FTS_DOC_ID
+create or replace table t (a int) with system versioning;
+alter table t drop column a;
+ERROR HY000: Table `t` must have at least one temporal column
+alter table t drop column a, drop column a;
+ERROR 42000: Can't DROP COLUMN `a`; check that it exists
 drop database test;
 create database test;

mysql-test/suite/versioning/t/alter.test

@@ -377,6 +377,12 @@ create or replace table t (c text) engine=innodb with system versioning;
 show create table t;
 alter table t add fulltext key (c);
 
+create or replace table t (a int) with system versioning;
+--error ER_VERS_TABLE_MUST_HAVE_COLUMNS
+alter table t drop column a;
+--error ER_CANT_DROP_FIELD_OR_KEY
+alter table t drop column a, drop column a;
+
 
 drop database test;
 create database test;

sql/sql_table.cc

@@ -8363,6 +8363,13 @@ mysql_prepare_alter_table(THD *thd, TABLE *table,
     }
   }
 
+  if (table->versioned() && !(alter_info->flags & Alter_info::ALTER_DROP_SYSTEM_VERSIONING) &&
+      new_create_list.elements == VERSIONING_FIELDS)
+  {
+    my_error(ER_VERS_TABLE_MUST_HAVE_COLUMNS, MYF(0), table->s->table_name.str);
+    goto err;
+  }
+
   if (!create_info->comment.str)
   {
     create_info->comment.str= table->s->comment.str;