小技巧-不写函数实现split截取
 
1. 不写函数实现split截取
 
场景:dayNewStat+meilishuo+ipad+2003 (dayNewStat+meilishuo+iphone+2003)(dayNewStat+meilishuo+android+2003) 只取最后一位
 
设想:split('+')[-1]  (python写法)
 
实现:有严格的格式要求,取巧方法,无技术含量
 
1
substring(record_tag,locate('+',replace(record_tag,'dayNewStat+meilishuo+',' dayNewStat-meilishuo-')))
2. having + min + if

 

 
场景:只要status是ok的,且id最小
 
id      type     status

001    aaa      ok

002    aaa      error

010    aaa      ok

003    bbb     ok

 

 
实现:去重 & 按条件筛选
 
1
select stat_date,record_tag,substring(record_tag,locate('+',replace(record_tag,'dayNewStat+meilishuo+',' dayNewStat-meilishuo-'))) as client_id,attr_value
2
from t_stat_daynew_classify_201306
3
where  record_type='dayNewStat+app+device+clientID' and record_tag like 'dayNewStat+meilishuo+%'  and attr_name ='totalDID' and attr_name_hash = 1380872519 and record_type_hash = 2039497004
4
group by stat_date,record_tag
5
having min(id) and if( (client_id>10000 and record_tag like 'dayNewStat+meilishuo+android%') or (client_id>2000 and client_id<5000 and record_tag like 'dayNewStat+meilishuo+ipad%')  or (client_id>5000 and client_id<10000),'ok','del' ) = 'ok' order by stat_date,client_id