<!-- 利用hashmap传递参数数据查询用户 -->
<select id ="selectUserById4Map" parameterType="string" resultType="hashmap" >
select
<include refid ="allColumns" />
from user where id = #{id}
</select>
<!-- 利用hashmap传递参数数据插入用户信息 -->
<select id ="insertUser4Map" parameterType="hashmap" >
insert into user(id,name,age,address) values(#{id},#{name},#{age},#{address})
</select>
<!-- 模糊查询 -->
<select id ="selectUserByCondition3" parameterType="com.judy.mybatis.domain.User" resultType="com.judy.mybatis.domain.User" >
select * from user where 1 = 1
<if test ="id!=null" >
and id = #{id}
</if>
<if test ="name!=null" >
and name like '%${name}%'
</if>
<if test ="age!=null" >
and age = #{age}
</if>
<if test ="address!=null" >
and address = #{address}
</if>
</select>
<!-- 利用动态sql语句更新user数据 -->
<insert id ="updateUserByCondition" parameterType="com.judy.mybatis.domain.User" >
update user
<set>
<if test ="name!=null" >
name = #{name}
</if>
<if test ="age!=null" >
age = #{age}
</if>
<if test ="address!=null" >
address = #{address}
</if>
</set>
where id=#{id}
</insert>
<!-- 动态seql语句查询用户 -->
<select id ="selectUserByCondition" parameterType="com.judy.mybatis.domain.User" resultType="com.judy.mybatis.domain.User" >
select * from user where 1 = 1
<if test ="id!=null" >
and id = #{id}
</if>
<if test ="name!=null" >
and name = #{name}
</if>
<if test ="age!=null" >
and age = #{age}
</if>
<if test ="address!=null" >
and address = #{address}
</if>
</select>
<!-- 动态seql语句查询用户方式2 -->
<!-- 这种方式会自动根据是否有id，如果有没有id，那么第一个条件将不加and -->
<select id ="selectUserByCondition2" parameterType="com.judy.mybatis.domain.User" resultType="com.judy.mybatis.domain.User" >
select * from user
<where>
<if test ="id!=null" >
id = #{id}
</if>
<if test ="name!=null" >
and name = #{name}
</if>
<if test ="age!=null" >
and age = #{age}
</if>
<if test ="address!=null" >
and address = #{address}
</if>
</where>
</select>
<!-- 当字段很多的时候，可以通过下面这种方式抽取字段 -->
<sql id ="allColumns" >
id,name,age,address
</sql>
<!-- 如果在sqlMapConfig.xml中配置了别名，那么这里的resultType就可以直接写User -->
<select id ="selectUserById" parameterType="string" resultMap="userMap" >
select
<include refid ="allColumns" />
from user where id = #{id}
</select>
