xml中的sql语句样式代码

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="top.jztice5.mapper.PruductMapper">
    <!--
    注：标签不是select
    values后面写的是Brand类中的属性名字
    useGeneratedKeys 获取mysql自动生成的主键，自动封装到id属性值中
    keyProperty 实体类中主键的属性名 brand中id
    keyColumn tb_brand表中主键字段名字 id
     -->
    <!--   映射的接口方法 ：id后面的方法名 ；框架创建代理对象，当调用映射的接口方法后，代理对象就会找到并执行对应id的sql语句，再将结果集或需要的数据返回到实体类中-->
    <!--    在创建代理对象的时候就会加载映射文件 （mapper.xml）-->
    <!--    添加-->
    <insert id="insert" useGeneratedKeys="true" keyColumn="id" keyProperty="id">
        insert into tb_brand
        values (null, #{brandName}, #{companyName}, #{ordered}, #{description}, #{status})
    </insert>
    <!--    修改-->
    <update id="update">
        update tb_brand
        <set>
            <if test="brandName !=null and brandName !=''">
                brand_name =#{brandName},
            </if>
            <if test="companyName != null and companyName !=''">
                company_name =#{companyName},
            </if>
            <if test="ordered != null">
                ordered=#{ordered},
            </if>
            <if test="description!=null and description!=''">
                description=#{description},
            </if>
            <if test="status!=null">
                status = #{status}
            </if>
        </set>
        <where>
            id = #{id}
        </where>
    </update>
    <!--   删除-->
    <delete id="delete">
        delete
        from tb_brand
        where id = #{id}
    </delete>
    <!--    批量删除:   数组-->
    <delete id="deletes">
        delete from tb_brand
        where id in
--               因为数组有别名：ids，如果没有别名，这里是数组的话，默认写 array ；
        <foreach collection="ids" open="(" separator="," close=")" item="id">
            #{id}
        </foreach>
    </delete>
    <!--    批量删除 ：  集合-->
    <delete id="deletesList">
        delete from tb_brand
        where id in
        <foreach collection="collection" open="(" separator="," close=")" item="id">
            #{id}
        </foreach>
    </delete>
    <!--    查询-->
    <!--只有查询才需要定义结果集的返回值类型-->
    <select id="selectOne" resultType="top.jztice5.pojo.Pruduct">
        select *
        from tb_brand
        where id = #{id};
        --     #：的底层是preparedStatement；
        --     $：的底层是Statement，会有sql注入异常；(两个不能同时存在)
    </select>
//多条件查询：
    <select id="selectAll" resultType="top.jztice5.pojo.Pruduct">
        select * from tb_brand
        <where>
            <if test="status != null">
                `status`= #{status}
            </if>
            <if test="brandName != null and brandName !='' ">
                AND brand_Name like "%"#{brandName}"%"
            </if>
            <if test="companyName != null and companyName !='' ">
                AND company_Name like "%"#{companyName}"%"
            </if>
        </where>
    </select>
    <select id="selects" resultType="top.jztice5.pojo.Pruduct">
        select *
        from tb_brand;
    </select>
    <select id="selectList" resultType="top.jztice5.pojo.Pruduct">
        select *
        from tb_brand
        <where>
            <if test="status != null">
                status = 1
            </if>
        <if test="companyName != null and companyName !=''">
            and company_name = #{companyName}
        </if>
        <if test="brandName != null and brandName !=''">
            and brand_Name = #{brandName}
        </if>
        </where>
    </select>
</mapper>