COUNT(CASEWHEN条件THEN1ELSENULLEND) xxxGROUPBY分组字段 2.添加条件并去重的统计方案: COUNT(DISTINCTCASEWHEN条件THEN去重字段END) xxxGROUPBY分组字段 综合示例: SELECTdc.user_sourcesASsources,COUNT(CASEWHENdc.`count_type`IN(1,4)THEN1ELSENULLEND)ASdjNum1,COUNT(CASEWHENdc.`count_type`IN(2,5)THEN1E...
1.count(*) 、 count(n)、count(null)与count(fieldName) 2.distinct 与 count 连用 3.group by (多个字段) 与 count 实现分组计数 4.case when 语句与 count 连用实现按过滤计数 准备工作 -- 创建表 CREATETABLE`tb_student` ( `id`int(11)NOTNULL, `stu_name`varchar(255)CHARACTERSETutf8mb4DEFAULT...
where子句中的条件:主队是德国或者客队是德国,比如德国 和 A队比赛(德国是主队),进球的是A队,A队和德国比赛(德国是客队),进球的是A队,内联结的结果中入球球员有重复值,用distinct去重复值 比赛地点(比赛信息表game),和每个比赛地点的进球数(进球信息表goal:按比赛地点分组,对进球人员进行汇总count(player),要查...
Category:MySQL Server: DMLSeverity:S3 (Non-critical) Version:5.5+OS:Any Assigned to:Guilhem BichotCPU Architecture:Any Tags:case when,count,distinct,regression,tmp_table_size [27 Nov 2013 21:26] xiaobin lin Description:Consider a sql like: select count(distinct case when xxx then f end) fro...
(distinct case when type='completed' then email.id else null end ) ,3)as p from email left join user u1 on email.send_id=u1.id and u1.is_blacklist=0 left join user u2 on email.receive_id=u2.id and u2.is_blacklist=0 group by date order by date; MySQL里运行是的 但是牛客网上...
mysqlcount中使⽤casewhen带条件及去重SELECT CASE (SELECT NOW() > '2019-02-12 16:48:00')WHEN 1 THEN '男'WHEN 2 THEN '⼥'ELSE '未知'END as ages COUNT(CASE WHEN A.expire_time<{0} AND A.expire_time<>0 THEN A.expire_time END) AS disabled_total 对部分列去重 DISTINCT ucd...
count(distinct) image.png selecta.购买时间,count(distinct a.用户id)当日首次购买用户数,count(distinctcasewhentimestampdiff(month,a.购买时间,b.购买时间)<=1then a.用户idelsenullend)as此月复购用户数,count(distinctcasewhentimestampdiff(month,a.购买时间,b.购买时间)=3then a.用户idelsenullend)as第...
1. 2. 3. 4. 5. 6. 7. COUNT(CASEWHENA.expire_time<{0}ANDA.expire_time<>0THENA.expire_timeEND)ASdisabled_total 1. 对部分列去重 DISTINCTucd.course_id,ucd.user_idandCASEWHENucd.kind=0THENucd.kindEND 1.
mysql 聚集函数 count 使用详解 2016-04-25 14:52 −**总结:** 1.count(*) 、 count(n)、count(null)与count(fieldName) 2.distinct 与 count 连用 3.group by (多个字段) 与 count 实现分组计数 4.case when 语句与 count 连用实现按过滤计数 ##... ...
select a.登陆时间, count(distinct a.用户id) as 活跃用户数, count(distinct when 时间间隔=1 then 用户id else null end) as 次日留存数, count(distinct when 时间间隔=1 then 用户id else null end) as 次日留存数 / count(distinct a.用户id) as 次日留存率, count(distinct when 时间间隔=3 then...