时间:2022-12-09 09:57:23 | 栏目:JAVA代码 | 点击:次
MemberExample example = new MemberExample(); MemberExample.Criteria c1 = example.createCriteria(); c1.andOne(A).andTwo(B); MemberExample.Criteria c2 = example.createCriteria(); c2.andThree(C).andFour(D); example.or(c2);
思路 : 分拆 : A and ( B or C ) ==> ( A and B ) or ( A and C )
MemberExample example = new MemberExample(); MemberExample.Criteria c1 = example.createCriteria(); c1.andOne(A).andTwo(B); MemberExample.Criteria c2 = example.createCriteria(); c2.andOne(A).andThree(C); example.or(c2);
实例代码:
BaUserExample baUserExample = new BaUserExample(); Criteria criteria1 = baUserExample.createCriteria(); criteria1.andOrgIdEqualTo("1"); criteria1.andDeptIdEqualTo("1"); Criteria criteria2 = baUserExample.createCriteria(); criteria2.andUserNameEqualTo("name"); criteria2.andEmailLike("%test@%"); baUserExample.or(criteria2); userMapper.countByExample(baUserExample);
执行的sql语句:
==> Preparing: select count(*) from ba_user WHERE ( org_id = ? and dept_id = ? ) or( user_name = ? and email like ? )
暂时没找到直接的sql语句构造方法,但是经过转换还是可以实现的
根据逻辑表达式可以知道 a and ( b or c ) = ( a and b) or ( a and c )
所以就转变成第一种方法
举个例子,假如想要实现
select count(*) from ba_user WHERE userName like ? and ( dept_id is null or dept_id <>? )
可以转化为
select count(*) from ba_user WHERE (userName like ? and dept_id is null ) or ( userName like ? and dept_id <>? )
实例代码:
BaUserExample baUserExample = new BaUserExample(); Criteria criteria1 = baUserExample.createCriteria(); criteria1.andUserNameLike("%name%"); criteria1.andDeptIdIsNull(); Criteria criteria2 = baUserExample.createCriteria(); criteria2.andUserNameLike("%name%"); criteria2.andDeptIdNotEqualTo("1"); baUserExample.or(criteria2); userMapper.countByExample(baUserExample);
执行的sql语句:
==> Preparing: select count(*) from ba_user WHERE ( user_name like ? and dept_id is null ) or( user_name like ? and dept_id <> ? )
这算是一种取巧的方法吧,对于这样的问题可以自己编写mapper.xml文件,或者在代码里面过滤,还有一种思路就是修改Criteria的代码实现and和or功能调换(还没尝试过)。