mysql多表左连接查询例子参考

<select id="queryList" parameterType="map"
resultType="com.zhensheng.entity.BusAfficheEntityQuery">

<!-- 查询该用户的接收公告id -->
select
<include refid="afficheField" />
,person.is_readed AS isRead,dict.label AS modelName
from bus_affiche AS
affiche LEFT JOIN bus_affiche_person AS person
on affiche.id =
person.affiche_id AND person.person_id = #{userId}
JOIN
sys_dict AS dict
on dict.id = affiche.affiche_type
where
affiche.id in
(
select distinct
receive.missive_id
from
bus_affiche_receive AS receive
<where>
<!-- 用户id -->
receive.condition_value =
<if test="userId != null and userId != ''">
#{userId}
</if>
<!-- 部门id -->
or receive.condition_value in
<if test="orgId != null and orgId != ''">
<foreach collection="orgId" item="oId" open="(" separator=","
close=")">
#{oId}
</foreach>
</if>
<!-- 自定义组id -->
or receive.condition_value in
<if test="groupId != null ">
<foreach collection="groupId" item="gId" open="(" separator=","
close=")">
#{gId}
</foreach>
</if>
and del_flag = '0'
</where>
order by create_date desc
)
AND affiche.is_recall = '0'
AND
affiche.del_flag = '0'
AND affiche.publish_status = '2'

order by
affiche.create_date desc
<if test="offset != null and limit != null">
limit #{offset}, #{limit}
</if>
</select>

SELECT
affiche.id,
affiche.title,
affiche.content,
affiche.affiche_type,
affiche.publisher,
affiche.indate,
affiche.is_timing,
affiche.timing_time,
affiche.publish_status,
affiche.is_recall,
affiche.recall_time,
affiche.org_id,
affiche.create_by,
affiche.create_date,
affiche.update_by,
affiche.update_date,
affiche.remarks,
affiche.del_flag,
affiche.conditions,
person.is_readed AS isRead,
dict.label AS modelName
FROM

bus_affiche AS affiche
LEFT JOIN bus_affiche_person AS person
on affiche.id = person.affiche_id
AND person.person_id = '1'
JOIN sys_dict AS dict

ON dict.id = affiche.affiche_type
where
affiche.id IN

(
SELECT DISTINCT
receive.missive_id
FROM
bus_affiche_receive AS receive
WHERE
receive.condition_value = '1'
OR receive.condition_value IN ('1', '3')
OR receive.condition_value IN ('1', '3')
AND del_flag = '0'
ORDER BY
create_date DESC
)

AND affiche.is_recall = '0'
AND affiche.del_flag = '0'
AND affiche.publish_status = '2'
ORDER BY
affiche.create_date DESC
LIMIT 1, 3

SELECT
missive.id,
missive.title,
missive.publish_time,
missive.create_by_name AS publish,
reply_title,
reply.create_by_name,
reply.replyCount
FROM
bus_missive_person person
LEFT JOIN bus_missive missive ON person.missive_id = missive.id
LEFT JOIN (
SELECT
count(id) replyCount,
reply_title,
create_by_name,
missive_person_id
FROM
(
SELECT
*
FROM
bus_missive_session
ORDER BY
reply_time DESC
) i
GROUP BY
missive_person_id
) reply ON person.id = reply.missive_person_id
WHERE
(
send_person_id = '1'
AND send_del = '1'
)
OR (
person_id = '1'
AND pernson_del = '1'
)

select gw.missive_id,missive.title,missive.publish_time,missive.create_by_name as publish,reply_title,reply.create_by_name,reply.replyCount,
(case  when person.create_by='1' and person.is_readed='0' then '0'
when person.create_by='1' and person.is_readed='1' then '1'
else person.send_readed end) isBlod
from (

select receive.missive_id as missive_id from bus_missive_receive receive
where (receive.condition_key='Person' and receive.condition_value='1')
or  (receive.condition_key='Dept' and receive.condition_value='1')
or  (receive.condition_key='Group' and receive.condition_value='3')
union
select id as missive_id from bus_missive
where create_by ='1') gw
left join bus_missive_person person on gw.missive_id = person.missive_id
left join bus_missive missive on person.missive_id = missive.id
left join (
select count(id) replyCount,reply_title,create_by_name,missive_person_id
from (select * from bus_missive_session order by reply_time desc) i group by missive_person_id) reply on person.id = reply.missive_person_id
where (send_person_id = '1') or (person_id = '1')

//where (send_person_id = '1' and send_del='0') or (person_id = '1' and pernson_del='0')