mybatis 使用（5）动态SQL

<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mybatis.mapper.UserInfoMapper">

	<!-- 动态SQL之<if>元素 -->
	<select id="findUserInfoByUserNameWithIf" parameterType="UserInfo"
		resultType="UserInfo">
		select * from user_info ui
		<if test="userName != null and userName != ''">
			where ui.userName LIKE CONCAT(CONCAT('%',#{userName}),'%')
		</if>
	</select>

	<!-- 动态SQL之<where>、<if>元素 -->
	<select id="findUserInfoByUserNameAndStatus" parameterType="UserInfo"
		resultType="UserInfo">
		select * from user_info ui
		<where>
			<if test="userName!=null and userName!=''">
				ui.userName LIKE CONCAT(CONCAT('%', #{userName}),'%')
			</if>
			<if test="status>-1">
				and ui.status = #{status}
			</if>
		</where>
	</select>

	<!-- 动态SQL之<set>、<if>元素 -->
	<update id="updateUserInfo2" parameterType="UserInfo">
		update user_info ui
		<set>
			<if test="userName!=null and userName!=''">
				ui.userName=#{userName},
			</if>
			<if test="password!=null and password!=''">
				ui.password=#{password}
			</if>
		</set>
		where ui.id=#{id}
	</update>


	<!-- 动态SQL之<trim>元素替代<where>元素 -->
	<select id="findUserInfoByUserNameWithIf_Trim" parameterType="UserInfo"
		resultType="UserInfo">
		select * from user_info ui
		<trim prefix="where" prefixOverrides="and|or">
			<if test="userName!=null and userName!=''">
				ui.userName LIKE CONCAT(CONCAT('%', #{userName}),'%')
			</if>
			<if test="status>-1">
				and ui.status = #{status}
			</if>
		</trim>
	</select>

	<!-- 动态SQL之<trim>元素替代<set>元素 -->
	<update id="updateUserInfo2_trim" parameterType="UserInfo">
		update user_info ui
		<trim prefix="set" suffixOverrides=",">
			<if test="userName!=null and userName!=''">
				ui.userName=#{userName},
			</if>
			<if test="password!=null and password!=''">
				ui.password=#{password}
			</if>
		</trim>
		where ui.id=#{id}
	</update>

	<!-- 动态SQL之<choose>、<when>和<otherwise>元素 -->
	<select id="findUserInfo_Choose" parameterType="UserInfo"
		resultType="UserInfo">
		select * from user_info ui
		<where>
			<choose>
				<when test="userName!=null and userName!=''">
					ui.userName LIKE
					CONCAT(CONCAT('%',#{userName}),'%')
				</when>
				<when test="status>-1">
					and ui.status = #{status}
				</when>
				<otherwise>
				</otherwise>
			</choose>
		</where>
	</select>

	<!-- 动态SQL之<foreach>元素 -->
	<select id="findUserInfoByIds" resultType="UserInfo">
		select * from user_info ui where ui.id in
		<foreach collection="list" item="ids" open="(" separator=","
			close=")">
			#{ids}
		</foreach>
	</select>

	<select id="findUserInfoByIds2" resultType="UserInfo">
		select * from user_info ui where ui.id in
		<foreach collection="array" item="ids" open="(" separator=","
			close=")">
			#{ids}
		</foreach>
	</select>



	<!-- 根据用户编号获取用户信息 -->
	<select id="findUserInfoById" parameterType="int" resultType="UserInfo">
		select *
		from user_info where id = #{id}
	</select>

	<!-- 根据用户名模糊查询用户 -->
	<select id="findUserInfoByUserName" parameterType="String"
		resultType="UserInfo">
		select * from user_info where userName like
		CONCAT(CONCAT('%',#{userName}),'%')
	</select>

	<!-- 添加用户 -->
	<insert id="addUserInfo" parameterType="UserInfo">
		insert into
		user_info(userName,password) values(#{userName},#{password})
	</insert>

	<!-- 修改用户信息 -->
	<update id="updateUserInfo" parameterType="UserInfo">
		update user_info set
		userName=#{userName}, password=#{password} where id=#{id}
	</update>

	<!-- 根据用户编号删除用户 -->
	<delete id="deleteUserInfo" parameterType="int">
		delete from user_info
		where id=#{id}
	</delete>

</mapper>