Mybatis-Plus中or()的使用避坑_mybatis plus (or)

1.连接 or()

当需要简单的将两个条件或连接,则最直接的写法为:

QueryWrapper<User> queryWrapper = new QueryWrapper<User>().
eq("status",0).
or().
eq("status",1);
 
//sql条件为  select * from user where status=0 or status=1

2.连接 or()

当多个条件共同拼接,则最直接的写法为: 要么把or()拼接放最前面，要么用queryWrapper.and(

qr.eq("status", 1).or().like("status", 2)），要不查询的数据会有偏差，queryWrapper.and相当于把两个条件（）一块；

QueryWrapper<User> queryWrapper = new QueryWrapper<User>().
eq("status",0).
or().
eq("status",1)
eq("user_name","张三");
 
//sql条件为  select * from user where status=0 or status=1 and user_name='张三'
 
 
 
 
QueryWrapper<User> queryWrapper = new QueryWrapper<User>().
eq("user_name","张三").
eq("status",0).
or().
eq("status",1);
 
//sql条件为  select * from user where user_name='张三' and  status=0 or status=1 
查询出来的数据和select * from user where status=0 or status=1 and  user_name='张三' 不一致
 
QueryWrapper<User> queryWrapper = new QueryWrapper<User>().
eq("user_name","张三").and(q->q.eq("status",0).
or().
eq("status",1));
 
select * from user where select * from user where user_name='张三' and (status=0 or status=1 ) 查询出来的数据和select * from user where status=0 or status=1 and  user_name='张三' 一致