代码示例

LambdaQueryWrapper<Disabled> queryWrapper = new LambdaQueryWrapper<>();
queryWrapper.eq(Disabled::getDcNumber, disabledNumber);
Disabled disabled = disabledMapper.selectOne(queryWrapper);
if (disabled == null){
    if (StringUtils.isNotBlank(encrypt)){
        // 用加密后的残疾人证号去数据库查询
        queryWrapper.eq(Disabled::getDcNumber, encrypt);
        disabled = disabledMapper.selectOne(queryWrapper);
    }
}

第一次查询：

==>  Preparing: SELECT ID... FROM DISABLED WHERE (DC_NUMBER = ?)
==> Parameters: 330**5912(String)正常的残疾证号，我这里是为了保护隐私，随便测试的
<==      Total: 0

第二次查询：

==>  Preparing: SELECT ID... FROM DISABLED WHERE (DC_NUMBER = ? AND DC_NUMBER = ?)
==> Parameters: 330**5912(String), 8480**ddtv458e(String)
<==      Total: 0

LambdaQueryWrapper<Disabled> queryWrapper = new LambdaQueryWrapper<>();
queryWrapper.eq(Disabled::getDcNumber, disabledNumber);
queryWrapper.eq(Disabled::getDcNumber, encrypt);

总结：对同一字段进行两次eq()，mybatis把两个条件叠加查询了