如何在网站上做关键词,网站建设与维护实训,莆田兼职做外贸网站,邮箱域名可以做网站吗case when 在sql 中非常方便数据不同维度统计#xff0c;但是也会出现mysql 索引不命中问题#xff0c;当多个case 出现时#xff0c;需要提取出来到where里面优化
优化后
SELECT date(RecordTime) AS date, count( DISTINCT CASE WHEN Param 1 …case when 在sql 中非常方便数据不同维度统计但是也会出现mysql 索引不命中问题当多个case 出现时需要提取出来到where里面优化
优化后
SELECT date(RecordTime) AS date, count( DISTINCT CASE WHEN Param 1 THEN UserID END ) AS h, count( DISTINCT CASE WHEN Param 2 THEN UserID END ) AS s, count( DISTINCT CASE WHEN Param 4 THEN UserID END ) AS z FROM user_prop_log_202310 WHERE Category 42 GROUP BY DATE(RecordTime) 优化前
SELECT date(RecordTime) AS date, count( DISTINCT CASE WHEN Category 42 AND Param 1 THEN UserID END ) AS h, count( DISTINCT CASE WHEN Category 42 AND Param 2 THEN UserID END ) AS s, count( DISTINCT CASE WHEN Category 42 AND Param 4 THEN UserID END ) AS z FROM user_prop_log_202310 GROUP BY DATE(RecordTime)
