informix的查询，同字段多条更改，增加字段，php 执行sql语句，substr()和mb_substr()

select * from databases_name:table_name where col_name1="1" and col_name2="2" and col_name3="1" order by id // order by id 为通过id值排序

alter table atabases_name:table_name ADD wtag char(1) default "0" //新增wtag字段,默认值为0，不知道为啥错不能执行，错误代码是-556

update atabases_name:table_name set  col_name="1" where col_name1 in ("68","71","84","82","1","50","8","92","24")//使用set  in  对满足条件col_name1字段值为("68","71","84","82","1","50","8","92","24")的记录把col_name 的值修改为"1"

php 执行sql语句：

  $sql = "select col_name1,col_name2,col_name3,col_name4 ,(select count(*) from database_name:table_name

                    where userid='" . $_SESSION['userid'] . "' and col_name5=a.con_name5),col-name6

                   from portal:sys_list&