<set>
<
if test="username !=null">username=#{username},</
if>
<
if test="password !=null">password=#{password},</
if>
<
if test="clazznumber !=null">clazznumber=#{clazznumber},</
if>
<
if test="clazzname !=null">clazzname=#{clazzname},</
if>
<
if test="sex !=null">sex=#{sex},</
if>
<
if test="address !=null">address=#{address},</
if>
<
if test="email !=null">email=#{email},</
if>
<
if test="phone !=null">phone=#{phone},</
if>
<
if test="flag !=null">flag=#{flag},</
if>
</set>
where id=
#{id}
</update>
<!-- 动态查询用户信息,返回可以是一个集合 -->
<select id="DynamicSelectStu" parameterType="hashmap" resultType="Student">
select * from student where flag=1
<choose>
<when test="id !=null">and id = #{id}</when>
<when test="username != null"> and username = #{username}</when>
<otherwise>
and sex = 1
</otherwise>
</choose>
</select>
<!-- 方法二，防止为传入参数查询报错 -->
<!-- 使用<where>防止未传入参数报错 -->
<select id="DynamicSelectStu2" parameterType="hashmap" resultType="Student">
select *
from student
<where>
<
if test="id !=null"> id=#{id}</
if>
<
if test="username !=null"> username=#{username}</
if>
<
if test="flag !=null"> flag=#{flag}</
if>
</where>
</select>
<select id="DynamicSelectStuIn" resultType="Student">
select *
from student where id in
<foreach item="item" index="index" collection="list"
open="(" separator="," close=")" >
#{item}
</foreach>
</select>
<!-- bind模糊查询 -->
<select id="DynamicSelectStuLikeName" parameterType="Student" resultType="Student">
<bind name="pattern" value="‘%‘ + _parameter.getUsername() +‘%‘"/>
select *
from student where username like #{pattern}
</select>
Mybatis动态SQL
标签：-- one null 标点符号 动态sql 使用 ber 防止 each
