src/main/resources/mapper/PostMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.pt5.pthouduan.mapper.PostMapper">

    <!-- 插入帖子 -->
    <insert id="save" parameterType="com.pt5.pthouduan.entity.Post"
            useGeneratedKeys="true" keyProperty="postid" keyColumn="postid">
        INSERT INTO post (
            userid,
            photo,
            rannge,
            is_pinned,
            post_title,
            post_content,
            postCreatedTime,
            updated_time,
            tags,
            likes
        ) VALUES (
                     #{userid},
                     #{photo},
                     #{rannge},
                     #{is_pinned},
                     #{post_title},
                     #{post_content},
                     #{postCreatedTime},
                     #{updated_time},
                     #{tags},
                     COALESCE(#{likes}, 0)
                 )
    </insert>

    <!-- 删除帖子 -->
    <delete id="deleteByPostid" parameterType="int">
        DELETE FROM post WHERE postid = #{postid}
    </delete>

    <!-- 更新帖子 -->
    <update id="updatePost" parameterType="com.pt5.pthouduan.entity.Post">
        UPDATE post
        SET
            userid = #{userid},
            photo = #{photo},
            rannge = #{rannge},
            updated_time = #{updated_time},
            is_pinned = #{is_pinned},
            post_title = #{post_title},
            post_content = #{post_content},
            postCreatedTime = #{postCreatedTime},
            tags = #{tags},
            likes = COALESCE(#{likes}, 0)
        WHERE postid = #{postid}
    </update>

    <!-- 模糊搜索帖子 -->
    <select id="searchByKeyword" resultType="com.pt5.pthouduan.entity.Post">
        SELECT * FROM post
        WHERE post_title LIKE CONCAT('%', #{keyword}, '%')
           OR tags LIKE CONCAT('%', #{keyword}, '%')
    </select>

    <!-- 点赞 +1 -->
    <update id="incrementLikes" parameterType="int">
        UPDATE post
        SET likes = likes + 1
        WHERE postid = #{postid}
    </update>

    <!-- 取消点赞 -->
    <update id="decrementLikes" parameterType="int">
        UPDATE post
        SET likes = CASE WHEN likes > 0 THEN likes - 1 ELSE 0 END
        WHERE postid = #{postid}
    </update>

    <!-- 更新置顶状态 -->
    <update id="updatePinnedStatus" parameterType="map">
        UPDATE post
        SET is_pinned = #{isPinned}
        WHERE postid = #{postid}
    </update>

    <!-- 根据用户 ID 查询其所有帖子 -->
    <select id="findByUserid" resultType="com.pt5.pthouduan.entity.Post">
        SELECT * FROM post
        WHERE userid = #{userid}
    </select>

    <!-- 查询所有置顶帖子 -->
    <select id="findPinnedPosts" resultType="com.pt5.pthouduan.entity.Post">
        SELECT * FROM post
        WHERE is_pinned = TRUE
    </select>

    <!-- 查询所有帖子，按置顶优先、创建时间倒序 -->
    <select id="selectAllSorted" resultType="com.pt5.pthouduan.entity.Post">
        SELECT * FROM post
        ORDER BY is_pinned DESC, postCreatedTime DESC
    </select>

    <!-- ✅ 根据 postid 查询单个帖子 -->
    <select id="selectById" parameterType="int" resultType="com.pt5.pthouduan.entity.Post">
        SELECT * FROM post
        WHERE postid = #{postid}
    </select>

</mapper>