mybatis动态sql语法

"1.0" encoding="UTF-8" ?>
mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.qvfan.mybatistest.mapper.EmpMapper">
    <sql id="commonSelect">
        select id,username,password,name,gender,image,job,entrydate,dept_id,create_time,update_time
        from emp
    sql>
    
    <select id="list" resultType="com.qvfan.mybatistest.pojo.Emp">
        <include refid="commonSelect">include>
        <where>
          <if test="name != null">
            name like concat('%', #{name}, '%')
          if>
          <if test="gender != null">
              and gender = #{gender}
          if>
          <if test="begin != null and end != null">
              and entrydate between #{begin} and #{end}
          if>
        where>
        order by update_time desc
    select>
    
    <update id="update2" >
        update emp
        <set>
            <if test="username != null">username =#{username},if>
            <if test="name != null">name=#{name},if>
            <if test="gender != null">gender=#{gender},if>
            <if test="image != null">image=#{image},if>
            <if test="job != null">job=#{job},if>
            <if test="entrydate != null">entrydate=#{entrydate},if>
            <if test="deptId != null">dept_id=#{deptId},if>
            <if test="updateTime != null">update_time=#{updateTime}if>
        set>
        where id = #{id};
    update>
    
    <delete id="deleteById">
        delete from emp  where id in
          <foreach collection="ids" item="id" separator="," open="(" close=")">
                #{id}
          foreach>
    delete>
mapper>

以上

查询使用了sql include 将通用的抽离出来,用where if 来进行判断 从而实现 动态sql

更新使用了set if

删除使用了foreach 来进行批量删除