src/main/resources/mapper/PostMapper.xml

.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.example.g8backend.mapper.PostMapper">
    <select id="getPostsByUserId" resultType="com.example.g8backend.entity.Post">
        SELECT * FROM posts WHERE user_id = #{userId}
    </select>

    <select id="getPostLikeCount" resultType="java.lang.Long">
        SELECT COUNT(*) FROM post_likes WHERE post_id = #{postId}
    </select>

    <insert id="likePost">
        INSERT INTO post_likes (user_id, post_id)
        VALUES (#{userId}, #{postId})
    </insert>

    <delete id="unlikePost">
        DELETE FROM post_likes 
        WHERE user_id = #{userId} AND post_id = #{postId}
    </delete>
</mapper>