window-functions

问题 I have a HDFS file with 50 Million records and raw file size is 50 GB. I am trying to load this in a hive table and create unique id for all rows using the below, while loading. I am using Hive 1.1.0-cdh5.16.1. row_number() over(order by event_id, user_id, timestamp) as id While executing I see that in the reduce step, 40 reducers are assigned. Average time for 39 Reducers is about 2 mins whereas the last reducer takes about 25 mins which clearly makes me believe that most of the data is

问题 Does anyone know how to replace nulls in a column with a string until it hits a new string then that string replaces all null values below it? I have a column that looks like this Original Column: PAST_DUE_COL 91 or more days pastdue Null Null 61-90 days past due Null Null 31-60 days past due Null 0-30 days past due Null Null Null Expected Result Column: PAST_DUE_COL 91 or more days past due 91 or more days past due 91 or more days past due 61-90 days past due 61-90 days past due 61-90 days

问题 I have the following query where I am trying to select all records, ordered by date, until the second time EmailApproved = 1 is found. The second record where EmailApproved = 1 should not be selected. declare @Test table (id int, EmailApproved bit, Created datetime) insert into @Test (id, EmailApproved, Created) values (1,0,'2011-03-07 03:58:58.423') , (2,0,'2011-02-21 04:55:52.103') , (3,0,'2011-01-29 13:24:02.103') , (4,1,'2010-10-12 14:41:54.217') , (5,0,'2010-10-12 14:34:15.903') , (6,0,

来源： https://stackoverflow.com/questions/63072200/any-better-way-to-return-1-value-for-multiple-row-in-case-when-by-window-functio

来源： https://stackoverflow.com/questions/63072200/any-better-way-to-return-1-value-for-multiple-row-in-case-when-by-window-functio

来源： https://stackoverflow.com/questions/64025450/select-first-in-and-last-out-time-different-date-and-null-condition-from-dat

来源： https://stackoverflow.com/questions/64025450/select-first-in-and-last-out-time-different-date-and-null-condition-from-dat

来源： https://stackoverflow.com/questions/63999745/query-to-assign-serial-number-for-rows-without-grouping-together-and-without-cha

来源： https://stackoverflow.com/questions/63999745/query-to-assign-serial-number-for-rows-without-grouping-together-and-without-cha

来源： https://stackoverflow.com/questions/57765698/problem-using-row-number-function-in-mariadb