we also has this demand, for derived dimension, lookup table is too big for memory, so put the name to measure is a good choice, I will work on it to support max on string.
2016-06-26 21:24 GMT+08:00 Li Yang <[email protected]>: > The best solution is to let Kylin support max on strings. Please open a > JIRA to track. > > On Thu, Jun 23, 2016 at 11:18 PM, ShaoFeng Shi <[email protected]> > wrote: > >> The new "Extended column" measure will match your case; It is a "Derived" >> column but on fact table; You can see more with KYLIN-1313. >> >> 2016-06-23 17:25 GMT+08:00 Hao Chen <[email protected]>: >> >> > Hi, all. >> > given a dimension table: >> > >> > dim_table{ >> > id_column int, >> > name_column string >> > } >> > >> > and a fact table: >> > fact_table{ >> > id_column int, >> > measure int >> > } >> > >> > usually we select with this sql: >> > select >> > dim.id_column, >> > max(dim.name_column), >> > sum(fact.measure) >> > from fact_table as fact >> > join dim_table as dim >> > on fact.id_column = dim.id_column >> > group by dim.id_column >> > >> > >> > we just want to get the name column. >> > one way is to add the name_column as a derived dimension. But it costs >> > memory and slow down query. >> > another way is make name_column as a measure with max as aggregation >> > function. But kylin do not support Max on string type column. >> > >> > Is there any better way to solve this problem? >> > thanks! >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > -- >> > 陈昊/Jerry Chen >> > >> > Tel: (+86)15013773175 >> > Email: jerrychen <[email protected]>[email protected] >> > P.C. 518055 >> > Add: 中国广东省深圳市西丽大学城清华园H楼205 >> > Room 205, Building H, Tsinghua Campus, The University Town, Shenzhen, >> > P.R.China >> > 清华大学计算机科学与技术系 >> > Department of Computer Science and Technology, Tsinghua University >> > >> >> >> >> -- >> Best regards, >> >> Shaofeng Shi >> > >
