Bailian-Al/ruoyi-demo/src/main/resources/mapper/demo/BrandCityTierMapper.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.ruoyi.demo.mapper.BrandCityTierMapper">
    <delete id="deleteAllById">
        DELETE
        FROM
            `bl_brand_city_tier`
        <foreach collection="ids" item="id" open="WHERE brand_id IN (" separator="," close=")">
            #{id,jdbcType=VARCHAR}
        </foreach>
    </delete>
    <select id="selectAllId" resultType="java.lang.String">
        SELECT DISTINCT
            brand_id
        FROM
            `bl_brand_city_tier`;
    </select>
    <select id="selectNoUse" resultType="java.lang.String">
        SELECT
        brand_id
        FROM
        `bl_brand_city_tier`
        GROUP BY
        brand_id
        HAVING COUNT(*) <![CDATA[<]]> #{num};
    </select>
</mapper>