查询两张表 并且对为空的值做默认值

select

u.User_pictureUrl,

u.User_phone,u.ID as userId,

u.user_nickname,

IFNULL(f.userFriend_status,3)as status ,

IFNULL(f.userFriend_comment,' ')as userFriend_comment,

IFNULL(f.userFriend_address,' ')as userFriend_address

from

tab_userinfo u

LEFT JOIN tab_userfriend f ON u.ID=f.userFriend_user_id

where

u.ID=#{userId}

mybatis中插入

insert into user_message

(

skip_id,user_id

)

values

(

ifnull(#{userMessage.skipId},"0"),

#{userMessage.userId}

)

等同于：

#{userMessage.skipId},

#{userMessage.skipSonId},

#{userMessage.jumpType},

"0",

"0",

0,

详见：https://blog..net/weixin_38137028/article/details/88245042