关于sql的条件查询问题

                " select orgid,polnum,sernum,chgitm,curcode from nposditem where "+
                " chgitm='FC001' and result='CL' and orgID=? and polnum=? "+
                " ) T01 "+
                " where "+
                " exists (select 1 from nposdplanDetail T02 "+
                "    where T01.orgID=T02.orgID and T01.polnum=T02.polnum "+
                "    and T01.curcode=T02.curcode "+
                "    and T01.sernum=T02.sernum and T02.chgitm=T01.chgitm "+
                "    and T02.changetype <> '1' "+
                "    and T02.isbeforeorafter='Y' "+
                "    and T02.reinstatable = '1'

我现在要把这条jdbc的sql改为mybatis，其中所有条件基本都改成java代码去实现，但是这个T02.changetype <> '1' 没看懂，哪位给解释一下

<>1，意思就是不等于1，，

即不大于 又不小于 不就是不等于？

nposdplanDetail 表的 changetype 字段 不等于 1