mybatis xml sql 语句的常用语句
mybatis xml sql 语句的常用语句
官网:https://mybatis.net.cn/dynamic-sql.html
1:提取公共的sql语句:
2:动态添加----sql语句:
代码:
<insert id="test1" parameterType="com.floor.shop.model.Product"> INSERT INTO product <trim prefix="(" suffix=")" suffixOverrides=","> <if test="productName!=null and productName!=''"> product_name, </if> <if test="stockNum!=null and stockNum!=''"> stock_num, </if> <if test="salePrice!=null and salePrice!=''"> sale_price, </if> </trim> values <trim prefix="(" suffix=")" suffixOverrides=","> <if test="productName!=null and productName!=''"> #{productName}, </if> <if test="stockNum!=null and stockNum!=''"> #{stockNum}, </if> <if test="salePrice!=null and salePrice!=''"> #{salePrice}, </if> </trim> </insert>
3:动态修改----sql语句:
4:增加前避免重复:
(当userName在数据库中不存在的情况下,增加到数据库)
5:修改或者新增获取受影响的行数:
6:新增自动获取主键(新增id):
7:dao多参数处理,不封装的情况下传递参数:
mapper中的sql语句不用添加参数类型(paramater=" ")
8:传入多个值的数组处理(foreach):
接口:
映射文件:
测试:
批量新增,数据采用list传入:
<insert id="saveCustomerOpenBankInfo" parameterType="List">
INSERT INTO resource_customer_openbank(id,open_name,account_number,open_bank,customer_id)
VALUES
<foreach item="item" collection="list" index="idx" open="" separator="," close="">
(#{item.id}, #{item.openName}, #{item.accountNumber},#{item.openBank},#{item.customerId})
</foreach>
</insert>
批量插入去重数据:
<!--插入用户角色信息 -->
<insert id="insertUserRole" parameterType="ArrayList" >
insert into usi_user_role (user_id,role_id)
<foreach collection="list" item="item" index="index" separator="union all">
select #{item.userid,jdbcType=VARCHAR},
#{item.roleid,jdbcType=VARCHAR} from dual where not exists(select * from usi_user_role
where user_id = #{item.userid,jdbcType=VARCHAR}
and role_id = #{item.roleid,jdbcType=VARCHAR})
</foreach>
</insert>
9、mybatis like 拼接、动态sql拼接:
1、CONCAT()拼接%:
SELECT * FROM t_usr WHERE name like CONCAT('%',#{name},'%')
2:bind:
SELECT *
FROM t_usr
WHERE
<if test="name !=null || name !=''">
<bind name="name" value="'%' + name + '%'"/>
name like #{name}
</if>