i use
my steps
1. create a new database ckdb on mysql, then  create table t1(a int, primary key(a)); and insert some rows
2. SET allow_experimental_database_materialize_mysql=1; at clickhouse, 
3. CREATE DATABASE ckdb ENGINE = MaterializeMySQL('127.0.0.1:3306', 'ckdb', 'root', 'A123b_456');
4. use ckdb and select * from t1 ok
5. create table dzm as select * from others in mysql ----> cannot see dzm in clickhouse, but if select * from t1, reports
```
Code: 48. DB::Exception: Received from localhost:9000. DB::Exception: The ckdb.dzm cannot be materialized, because there is no primary keys..
```
6. create table t2(a int,b int primary a);----> cannot see t2 in clickhouse, , but if select * from t1, reports
```
Code: 44. DB::Exception: Received from localhost:9000. DB::Exception: Sorting key cannot contain nullable columns.
```
<del>7. if i drop ckdb and recreate it, all tables can be selected </del>
7.if there are some 'bad' tables in a database, all tables in that database cannot be selected

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if (alter_command->column_name == default_after_column)
                        default_after_column = rewritten_command->col_decl->as<ASTColumnDeclaration>()->name;
                }
                else
                {
                    rewritten_command->column = std::make_shared<ASTIdentifier>(default_after_column);
                    rewritten_command->children.push_back(rewritten_command->column);
                    default_after_column = rewritten_command->col_decl->as<ASTColumnDeclaration>()->name;
                }
                rewritten_command->children.push_back(rewritten_command->col_decl);
                rewritten_alter_query->command_list->add(rewritten_command);
            }
        }
        else if (alter_command->type == MySQLParser::ASTAlterCommand::DROP_COLUMN)
        {
            auto rewritten_command = std::make_shared<ASTAlterCommand>();
            rewritten_command->type = ASTAlterCommand::DROP_COLUMN;
            rewritten_command->column = std::make_shared<ASTIdentifier>(alter_command->column_name);
            rewritten_alter_query->command_list->add(rewritten_command);
        }
        else if (alter_command->type == MySQLParser::ASTAlterCommand::RENAME_COLUMN)
        {
            if (alter_command->old_name != alter_command->column_name)
            {
                
                auto rewritten_command = std::make_shared<ASTAlterCommand>();
                rewritten_command->type = ASTAlterCommand::RENAME_COLUMN;
                rewritten_command->column = std::make_shared<ASTIdentifier>(alter_command->old_name);