mybatis使用心得总结
首先下面的总结是基于mysql数据库的其他数据库是不是一样不知道
1.模糊查询
使用concat()函数。CONCAT(str1,str2,...)
SELECT * from t_cbo_location_apply
and identity_type = #{identityType,jdbcType=INTEGER}
and address_structure like
concat("%",#{addressStructure,jdbcType=VARCHAR},"%")
2.大于号小于号
使用 标记将大于号和小于号圈起来
SELECT t1.*,t2.name,t2.id as orgId,1 as cond FROM t_pb_conference t1
INNER JOIN t_pb_organization t2
on t1.pb_id = t2.id
and #{nowDate,jdbcType=TIMESTAMP} and t1.status < 4 and t1.status >= 1]]>
and = #{nowDate,jdbcType=TIMESTAMP} and t1.status < 4 and t1.status >= 1]]>
and = 1]]>
and t1.status = 4
and t1.conference_type = #{conferenceType,jdbcType=INTEGER}
and t1.theme like concat("%",#{theme,jdbcType=VARCHAR},"%")
and t1.start_time between #{beginTime,jdbcType=VARCHAR} and #{endTime,jdbcType=VARCHAR}
and t1.pb_id in
#{id,jdbcType=BIGINT}
and t1.status > 0
order by t1.release_time desc3.批量更新数组（不是按照id批量设置某一个属性的值，而是更新多行数据）
UPDATE t_pb_conference
WHEN id = #{item.id,jdbcType=BIGINT} then #{item.status,jdbcType=INTEGER}
WHEN id = #{item.id,jdbcType=BIGINT} then #{item.version,jdbcType=INTEGER} + 1
id = #{item.id,jdbcType=BIGINT} and version = #{item.version,jdbcType=INTEGER}
这个sql需要传进来一个list ，updateList中是要更新的数据库队列的值。这里更新的条件是按照id和锁version同时满足。至于要更新的行的属性，只需要将item.xxx进行 替换就行
4.mybatis批量查询 结果集按照传入参数的顺序输出
这里我自己的例子找不到了 找了个网上的例子
5.mybatis 的insert动态语句
不要将字段和值写死，要改成动态的。虽然这样会多写很多代码。ε=(´ο｀*)))唉。
个人不太喜欢用代码生成器，生成了方法名字也得改。
INSERT INTO t_cbo_location_apply
resident_id,
community_id,
community_name,
org_id,
org_name,
address_id,
address_structure,
create_time,
update_time,
update_user_id,
identity_type,
apply_status,
enable,
version,
comment,
card_type,
card_num,
credentials_photo_ids,
resident_name,
#{residentId,jdbcType=BIGINT},
#{communityId,jdbcType=BIGINT},
#{communityName,jdbcType=VARCHAR},
#{orgId,jdbcType=BIGINT},
#{orgName,jdbcType=VARCHAR},
#{addressId,jdbcType=BIGINT},
#{addressStructure,jdbcType=VARCHAR},
#{createTime,jdbcType=TIMESTAMP},
#{updateTime,jdbcType=TIMESTAMP},
#{updateUserId,jdbcType=BIGINT},
#{identityType,jdbcType=INTEGER},
#{applyStatus,jdbcType=INTEGER},
#{enable,jdbcType=INTEGER},
#{version,jdbcType=INTEGER},
#{comment,jdbcType=INTEGER},
#{cardType,jdbcType=INTEGER},
#{cardNum,jdbcType=VARCHAR},
#{credentialsPhotoIds,jdbcType=VARCHAR},
#{residentName,jdbcType=VARCHAR},
6.GROUP_CONCAT()函数
写项目的时候碰上个需求，要将一个关联关系表的值展示成一个字段。网上找了一下用这个函数就行
SELECT a.*,b.extend_type FROM
(
SELECT DISTINCT t1.id,
t1.real_name,
t1.sex,
t1.birthday,
t1.card_num,
t1.mobile,
t1.`status`,
t2.identity_type,
t2.address_structure
from t_cbo_resident t1
INNER JOIN
(
SELECT * from t_cbo_location_apply
and apply_status = 1
and identity_type = #{identityType,jdbcType=INTEGER}
and address_structure like concat("%",#{addressStructure,jdbcType=VARCHAR},"%")
LIMIT 1
)t2 on t1.id = t2.resident_id) a
Left JOIN (
SELECT x.id,GROUP_CONCAT(y.extend_type) as extend_type from t_cbo_resident x
INNER JOIN t_cbo_resident_extend y on x.id = y.resident_id
and y.org_id = #{orgId,jdbcType=BIGINT}
GROUP BY x.id
) b
ON a.id = b.id
and a.real_name like concat("%",#{realName,jdbcType=VARCHAR},"%")
and a.card_num like concat("%",#{cardNum,jdbcType=VARCHAR},"%")
and a.mobile like concat("%",#{mobile,jdbcType=VARCHAR},"%")
and b.type like concat("%",#{extendType,jdbcType=VARCHAR},"%")
注意这里使用了这个函数将关联关系表的值查询出来 按照居民的id分类，最后的结果当做一个表去和别的表join链接
SELECT x.id,GROUP_CONCAT(y.extend_type) as extend_type from t_cbo_resident x
INNER JOIN t_cbo_resident_extend y on x.id = y.resident_id
and y.org_id = #{orgId,jdbcType=BIGINT}
GROUP BY x.id