<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.xiaKangan.mapper.EmpMapper">
<!--    SQL片段的重复使用--><!-- 将SQL代码放入sql标签中，可以在其他增删改查操作中引入id实现复用--><sql id="sqlSyntax">select * from emp where name like concat('%',#{name},'%') and gender= #{gender} andentrydate between #{begin} and #{end} order by update_time desc</sql><select id="cSearch" resultType="com.xiaKangan.pojo.Emp">-- 引入SQL片段<include refid="sqlSyntax"/>
--         select * from emp where name like concat('%',#{name},'%') and gender= #{gender} and
--                                 entrydate between #{begin} and #{end} order by update_time desc</select><!--    动态SQL条件查询--><select id="conditionSearch" resultType="com.xiaKangan.pojo.Emp">select *from emp
--      where标签当有至少一个条件成立时，生成SQLwhere语句，并且自动修正SQL语句<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><!--    动态SQL更新数据--><update id="update2">update empset-- 将SQL语句里面多余的语法结构删除掉，避免语法错误-- trim 标签中还有 prefixOverrides 删除语法中的前缀多余部分-- 在if语句的外层添加set标签也能纠正语法<trim suffixOverrides=","><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></trim><where>id = #{id}</where></update><!--    批量删除员工信息(18,19,21)--><delete id="deleteByIds">delete from emp where id in-- collection 遍历的集合-- item 遍历出来的元素-- separater 分隔符-- open 遍历开始前的符号-- close 遍历结束的符号<foreach collection="ids" item="id" separator="," open="(" close=")">#{id}</foreach></delete></mapper>

XML动态SQL图片文件