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  • 表的求和及计算

    DISTINCT() 过滤重复
    COUNT() 统计个数
    SELECT COUNT(DISTINCT(cateid)) FROM cs_goods ORDER BY cateid
    SELECT COUNT(*) FROM cs_goods

    SUM() 求和
    求price列总和
    SELECT SUM(price) FROM cs_goods
    求每个月总销售额
    SELECT SUM(price),SUBSTRING(FROM_UNIXTIME(createtime),1,7) AS ymonth FROM cs_goods GROUP BY ymonth;
    求每天总销售额
    SELECT SUM(price),DATE(FROM_UNIXTIME(createtime)) AS ymonth FROM cs_goods GROUP BY ymonth ORDER BY ymonth DESC;
    求每天销售额大于100的记录
    SELECT SUM(price) AS total,DATE(FROM_UNIXTIME(createtime)) AS ymonth FROM cs_goods GROUP BY ymonth HAVING total>100 ORDER BY ymonth DESC;

    AVG() 求平均
    求所有商品平均单价
    SELECT AVG(price) FROM cs_goods;
    求每个分类下商品平均单价
    SELECT AVG(a.price),a.cateid,b.category FROM cs_goods a INNER JOIN cs_category b ON(a.cateid=b.id) GROUP BY cateid;
    MAX() 求最大值
    求每个分类下最高单价
    SELECT MAX(a.price),a.cateid,b.category FROM cs_goods a INNER JOIN cs_category b ON(a.cateid=b.id) GROUP BY cateid;
    MIX() 求最小值
    求每个分类下最小单价
    SELECT MIX(a.price),a.cateid,b.category FROM cs_goods a INNER JOIN cs_category b ON(a.cateid=b.id) GROUP BY cateid;

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  • 原文地址:https://www.cnblogs.com/yucaiyun/p/6728660.html
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