SSM(三)Mybatis动态SQL
1.查询语句，where：
1 <resultMap id="xxx" type="xx..Student" autoMapping="false">...</resultMap> 2 <select id="findAll" resultMap="xxx"> 3 select * from student 4 <where> 5 <if test="stuNo!=null and stuNo!=''">and stuNo=#{stuNo}</if> 6 <if test="stuName!=null and stuName!=''">and stuName like '%' #{stuName} '%'</if> 7 </where> 8 </select>
2.插入语句，trim：
1 <insert id="saveAttendances"> 2 insert into tms_attendance 3 <trim prefix="(" suffixOverrides="," suffix=")"> 4 <if test="at_tid != null">at_tid,</if> 5 <if test="at_labnum != null">at_labnum,</if> 6 ... 7 </trim> 8 VALUES 9 <trim prefix="(" suffixOverrides="," suffix=")"> 10 <if test="at_tid != null">#{at_tid},</if> 11 <if test="at_labnum != null">#{at_labnum},</if> 12 ... 13 </trim> 14 </insert>
3.修改语句，trim：
1 <update id="editUserById" parameterType="cn.happy.entity.Smbms_user"> 2 update smbms_user 3 <trim prefix="set" suffixOverrides=","> 4 <if test="username !=null and username !=''">userName=#{username},</if> 5 <if test="userpassword !=null">userPassword=#{userpassword},</if> 6 </trim> 7 where id=#{id} 8 </update>
4.查询语句，foreach：
1 <select id="findByList" resultType="Student"> 2 select * from student 3 <if test="list.size>0"> 4 WHERE stuno in 5 <foreach collection="list" open="(" close=")" separator="," item="myid"> 6 #{myid} 7 </foreach> 8 </if> 9 </select>
