Hive count distinct multiple columns. You may encounter Lists, Hashes, or Lists of Hashes.

Hive count distinct multiple columns. Can I select two distinct columns in SQL? Yes, the DISTINCT clause can be applied to any valid SELECT query. table where partition_date = '12-01-2015' How can I just as quickly get counts from multiple partitions? Jan 1, 2023 · The COUNT () function returns the total count of rows in a column or a table. For eg: select avg (distinct c1,c2) from T Not sure how this relates to the Oct 13, 2017 · I have multiple columns in a table in hive having around 80 columns. Below are some of the examples we will see in details besides syntax, usage and return Jul 31, 2024 · SQL SELECT with DISTINCT on multiple columns: Multiple fields may also be added with DISTINCT clause. Below is my table: Table 1 id | type 1, law 1, law 1, law 2, [jira] Commented: (HIVE-287) support count ( John Sichi (JIRA) [jira] Commented: (HIVE-287) support count (Arvind Prabhakar (JIRA) Feb 10, 2017 · FROM pv_users GROUP BY pv_users. Once it is persisted, provided the column is deterministic and you are using "sane" database settings, it can be indexed and / or statistics can be created on it. Nov 11, 2020 · Have a list of about 100+ SQL Count Queries to run against a Hive Data Table, Looking for the most efficient way to run these queries. like select distinct (a, b, c, d) from table. tasks=50;Select COUNT (*) from (select Description Retrieve rows from zero or more tables. The DISTINCT clause in PostgreSQL is used to return only distinct (different) values. In order to count the number of distinct users by gender one could write the following query: HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Feb 27, 2019 · ALL and DISTINCT Clauses The ALL and DISTINCT options specify whether duplicate rows should be returned. WITH SESSION clause The WITH SESSION clause allows you to set session and catalog session property values applicable for the processing of the current SELECT statement only. Update, I am using Hive and Impala (both available to me) Dec 19, 2021 · As stated in the earlier article, Skewed tables are those in which some column values occur more frequently than others. In some DBs this can be done using "select distinct on x,y from tabel" but hive dosent support "distinct on" Oct 26, 2017 · can i do a count and distinct on 2 different columns in a single select statement in Impala Labels: Apache Hive Apache Impala Cloudera Hue Nisith HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) akshay gvs Asks: How to get distinct count over multiple columns in Hive SQL? I have a table that looks like this. The following example overrides the global So, distinct can definitely take advantage of parallelism. In this comprehensive guide, we will tackle this common need in detail through examples, code samples Dec 1, 2015 · For a partitioned Hive table (stored as ORC), I can count the rows in a partition very quickly with a query like this, presumably because Hive gets the count directly from table statistics: select count(*) from db. I have some questions and clarifcations regarding your feedback: bq. org/jira/browse/IMPALA-110 In particular, using NDV () iinstead of COUNT (DISTINCT) is much faster, but returns approximate results only. Let’s see these two ways with examples. Arvind Prabhakar commented on HIVE-287: --------------------------------------- Thanks for taking a look at this patch Namit. Basically, we use Hive Group by Query with Multiple columns on Hive tables. I need to apply the distinct clause on some of the columns and get the first values from the other columns also. In SQL, we can leverage inbuilt functions to combine columns and efficiently count distinct values across them. Hive sql optimization - detailed optimization of count (distinct) 1. My Query is lacking performance due to the creation of many MapReduce Jobs and im looking for a better solution. 43 Say I have a dataframe df with two or more columns, is there an easy way to use unique() or other R function to create a subset of unique combinations of two or more columns? I know I can use sqldf() and write an easy "SELECT DISTINCT var1, var2, varN" query, but I am looking for an R way of doing this. MyTable Col_A | Col_B A | 1 A | 1 A | 2 A | 2 A | 2 A | 3 b | 4 b | 4 b | 5 Expected Result Col_A | Col_B | Result A | 1 | 3 A | 1 | 3 A | 2 | 3 A | 2 | 3 A | 2 | 3 A | 3 | 3 b | 4 | 2 b | 4 | 2 b | 5 | 2 I tried the following code select *, count (distinct col_B) over (partition by col_A Below example explains the Hive count analytic function: Just like count function, sum Hive analytic function is used to compute the sum of columns or expression. count (*) – Returns the count of all rows in a table including rows containing NULL values. Oct 26, 2017 · That currently is not possible, sorry. Right now the count aggregate function is treated like any other function and is thus part of the general framework. Syntax: SUM(column | expression) OVER( window_spec) For example: Calculate sum insured amount of all patients within each department. HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Jun 20, 2018 · screen-shot-2018-06-19-at-104245-pm. HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Dec 12, 2024 · Note that for versions of Hive which don’t include HIVE-287, you’ll need to use COUNT (1) in place of COUNT (*). Is there a Hive equivalent? SELECT COUNT(*), FROM INFORMATION_ HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) How can I get row count from all tables using hive? I am interested in the database name, table name and row count HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) How to get the Count of distinct rows in hive? In HIVE, I tried getting the count of distinct rows in 2 methods, SELECT COUNT (*) FROM (SELECT DISTINCT columns FROM table); SELECT COUNT (DISTINCT columns) FROM table; Both are yielding DIFFERENT RESULTS. The SELECT DISTINCT is especially valuable in such cases. Jul 21, 2025 · Learn how to count distinct values in SQL with COUNT DISTINCT function. Below is a sample input/output requirement Simple select query that help DISTINCT operator The DISTINCT operator in a SELECT statement filters the result set to remove duplicates. Here’s how to do complex count statements to simplify queries. When working with SQL databases, it is common to face situation where you need to retrieve unique combinations of values across multiple columns. Optimize your data analysis process and efficiently explore and analyze large-scale data stored in 1 In HIVE, I tried getting the count of distinct rows in 2 methods, SELECT COUNT (*) FROM (SELECT DISTINCT columns FROM table); SELECT COUNT (DISTINCT columns) FROM table; Both are yielding DIFFERENT RESULTS. All the columns are of numeric type double/int. Apr 30, 2021 · I have a table that I am trying to gather metrics on the number of times a value appears in the tables based by the value itself. Queries are accessed at runtime as a list of queries stored in another Hive Table, generated by a different process. I think I should create a intermediate table which includes all the dimensions (including the serval kinds of ids), and then use spark-sql to calculate the distinct values separately (spark sql is really fast so ~~). How are they working differently? Thanks in advance. If i just do a tag,date it throws a parse exception Feb 7, 2025 · SQL COUNT() with DISTINCT: SQL COUNT() function with DISTINCT clause eliminates the repetitive appearance of a same data. The row does not mean entire row in the table but it means “row” as per column listed in the SELECT statement. Namit Jain commented on HIVE-287: --------------------------------- I am sorry about 1 and 3 - you can ignore those. I believe a distinct count of the computed column would be equivalent to your query. Hive should support multi-column distinct and at that point counting should work. For example, the following query returns the customer name from the name column, and returns the sum of all total prices as customer spend. DISTINCT keyword is used in SELECT statement in HIVE to fetch only unique rows. I want to calculate maximum temperature from temperature_data table corresponding to those years which have at least 2 entr Jul 12, 2016 · this is problematic, since I need to receive both X and Y but with X distinct. 1 and use Hive-on-MR as the execution engine. Select COUNT (Distinct user_id) from Dm_user where ds=20150701;With the DISTICNT function, all data is only shuffle to a reducer, causing the reducer data to tilt heavilyAfter optimization forSet mapred. Report potential security issues Hive HIVE-287 support count (*) and count distinct on multiple columns Export I wanted clarification as to how DISTINCT works, using a toy example below. HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Aug 24, 2022 · All you need to know about sql - Count Number of Columns In Hive , in addintion to SQL Count number of occurences of combinations and split into separate columns by count , Why does count ( distinct ) with NULL columns return 0 in Hive SQL? , mysql - How to count distinct values from two columns into one number (follow up) , tsql - T-SQL count number of different values across multiple columns HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Nov 27, 2017 · I am very new to HIVE and have an issue with distinct count and GROUP BY. DISTINCT specifies removal of duplicate rows from the result set. DISTINCT will eliminate those rows where all the selected fields are identical. Apr 26, 2023 · Like in SQL, Aggregate Functions in Hive can be used with or without GROUP BY functions however these aggregation functions are mostly used with GROUP BY hence, here I will cover examples of how to use aggregation functions with and without applying groups. That might give you 513,238 distinct rows. Current implementation has the limitation that no ORDER BY or window specification can be supported in the partitioning clause for performance reason. Jun 3, 2019 · I am working on a hive(1. In a table, a column may contain duplicate values; and sometimes, you only want to list the different (unique) values. How to count distinct values over multiple columns using SQL Often we want to count the number of distinct items from this table but the distinct is over multiple columns Method-1 Using a derived table (subquery) You can simply create a select distinct query and wrap it inside of a select count (*) sql, like shown below: SELECT COUNT(*) Sep 17, 2019 · This operation is a bit heavy to Hive cluster, but does its job. count (expr) – Returns the total number of rows for expression excluding null. Nov 4, 2023 · Handling data often involves identifying unique information across multiple attributes or columns. 1. In this case, the first stage of the query implementing DISTINCT can use more than one reducer. By chaining these you can get the count distinct of PySpark DataFrame. More importantly, the SELECT and GROUP BY lists should match -- all unaggregated columns should be in the GROUP BY: SELECT EmployeeName, SalesID, COUNT(DISTINCT workload) as Cases FROM t GROUP BY EmployeeName SalesID This allows you to return values from columns that are not directly part of the aggregation, including expressions using these columns, in a query. 0. reduce. SELECT id, personalemailtrim, personworksatnumberofbsbs, region More to the point in Hive - my key concern is that by modifying the grammar to make an exception for { {COUNT}}, we will be introducing a brittle coupling between the the parser and semantic analyzer. This should be independent of COUNT - so, all basically all aggregation functions should be supported with DISTINCT. Dec 28, 2021 · Skewed tables are those in which some column values occur more frequently than others. Feb 9, 2016 · I am looking for a way to count the number of columns in a table in Hive. This allows removing duplicates, grouping accurately, and gaining deeper insights. As a result, the reducer will not be overloaded. The COUNT() function counts the number of orders with the same customer_id. Jul 23, 2025 · The DISTINCT keyword retrieves unique values or records from a table, eliminating duplicates. I need to count the number of null values for each column in the table grouped by date. Aug 21, 2018 · Luckily, There are only two distinct value for col2 - val1, val2 but it will be bonus points if there is a solution to scale to many value other than two. Multiple properties are separated by commas. I think your syntax is wrong. We would like to show you a description here but the site won’t allow us. Select with distinct on multiple columns and order by clause. Queries like these each with a different wh Jul 23, 2025 · While SELECT DISTINCT is commonly used with a single column, its application on multiple columns requires a slightly more detailed understanding. The Hive version is 2. John Sichi commented on HIVE-287: --------------------------------- Yes, if you can do get it to work in the grammar itself (via a choice in the existing "function" rule), that would be best. John Sichi commented on HIVE-287: --------------------------------- For DISTINCT: we can check the function invocation itself (during semantic analysis) by calling supportsDistinct () immediately after instantiating the GenericUDAFEvaluator in SemanticAnalyzer. Formulas in Hive Automate are whitelisted Ruby methods, and therefore not all Ruby methods are supported. You can do that by following Jan 1, 2022 · Explore the syntax and various types of SELECT queries in Apache Hive with this comprehensive guide. Learn how to retrieve and manipulate data from tables using basic SELECT statements, WHERE clauses, aggregation functions, DISTINCT keyword, JOIN operations, ORDER BY and LIMIT clauses, and more. SELECT type , count (*) , count (DISTINCT u) , count (CASE WHEN plat=1 THEN u ELSE NULL END) , count (DISTINCT CASE WHEN plat=1 THEN u ELSE NULL END) , count (CASE WHEN (type=2 OR type=6) THEN u ELSE NULL END) , count (DISTINCT CASE WHEN Jun 4, 2019 · I have a table with two columns, I want to count the distinct values on Col_B over (conditioned by) Col_A. If none of these options are given, the default is ALL (all matching rows are returned). To remove duplicate values, you can use insert overwrite table in Hive using the DISTINCT keyword while selecting from the original table. Jan 6, 2019 · Query: select 2gusage,count(2gusage) from demo group by 2gusage; Output: MID 765153 HIGH 18095461 LOW 119069472 NULL 25997075 I tried the below query to find the count of NULL values Query select count(*) from demo where 2gusage is 'NULL'; Output 0 Kindly help me out with the query to find the count Mar 15, 2019 · Hadoop Hive SUM Analytic Function Just like count function, sum Hive analytic function is used to compute the sum of columns or expression. thanks again. Note, Hive supports SELECT DISTINCT * starting in release 1. HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Jun 12, 2019 · First, none of your queries have a FROM clause, so all should generate syntax errors. 1. Apr 26, 2017 · I want to count the occurrences of values columnwise and for each user. Here is what I understand your Jun 10, 2022 · I am getting two very different numbers for these seemingly similar queries on (hive) tables: select count(*) from test # result: 2609173 select distinct count(*) from test # result: 2609173 insert into testToo select distinct * from test # result: inserted 673065 rows Any recommendations on how I might be able to discern what is going on? Sep 16, 2013 · 0 Distinct is a keyword, not a function. Sum analytic function is used to compute the sum of all rows of table or rows within the groups. In addition to the basic data types (for example, string and integer), you may encounter more complex data structures that contain information about multiple items or multiple pieces of information about a single item. mytable This solution will scale to as many columns as you like, and will adjust for different numbers of columns if you want to run this on multiple tables. You may encounter Lists, Hashes, or Lists of Hashes. HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Mar 4, 2019 · If your RDMS supports COUNT(DISTINCT ), that's a simple aggregate query: SELECT mydate, product, COUNT(DISTINCT customer) FROM mytable GROUP BY mydate, product PS : it is usually not a good idea to name a column date, as this conflicts with the homonym sql datatype. My Table Feb 27, 2021 · In both traditional relational systems and big data technologies such as Apache Hive and Apache Impala, most of the functions specified in this series are common. This is typically used in combination with the count aggregate to get the number of distinct elements; but it can be used together with any aggregate function in the system. When applied to multiple columns, DISTINCT ensures that no two rows have identical values across all selected columns. An aggregate function or aggregation function in database management is a function where the values of multiple rows are grouped together to form a single summary value. Is there a way to have multiple columns in the then clause. HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Aug 17, 2015 · SELECT (COUNT(*) - COUNT(a))/COUNT(*) AS a_nulls, (COUNT(*) - COUNT(b))/COUNT(*) AS b_nulls, (COUNT(*) - COUNT(c))/COUNT(*) AS c_nulls FROM myschema. It is applied with the SELECT statement to obtain unique values of one or more columns. to expl HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Mar 22, 2017 · Hello All, I am trying to group all records for a table by "date" which is also a column. Or make the method name checkDistinct and allow the UDAF to throw the exception itself How do I select distinct on all columns? The DISTINCT keyword is applied to all columns. The combination of COUNT() and OVER(PARTITION BY) is more powerful than using the COUNT() function alone because it allows us to get the number of rows for each specific value of a column. Nov 28, 2017 · Distinct support in Hive 2. However, one other important point is that a tuple is counted only if none of the individual values in the tuple is null. If I don't do an operation on mdse_item_i like cast it to a bigint, it doesn't always count them correctly. It applies to all columns you list in your select clause. SELECT DISTINCT column_name FROM table_name; Understanding GROUP BY and HAVING in Hive In Hive, the GROUP BY clause is used in a SELECT query to group rows with identical values in specified columns into summary rows, typically for aggregation operations like SUM, COUNT, AVG, MIN, or MAX. Query and output as Nov 5, 2015 · COUNT(DISTINCT() only counts distinct values when ALL specified fields are non-null. countDistinct() is a SQL function that could be used to get the count distinct of the selected multiple columns. The SQL SELECT DISTINCT statement retrieve the unique records, by removing the duplicates from the specified Column in the SELECT Statement. Master SQL techniques for unique data analysis with multiple columns and aggregate functions. 4-cdh) code optimization on MapReduce, in my project we have used lot of count distinct operation with groupby clause, an example hql is shown below. Boost your career with Data Engineering Courses!! In Apache Hive Tutorial, for grouping particular column values mentioned with the group by Query. I imagine that as Hive matures, such problems will be fixed. 2. In the second stage, the mapper will have less output just for the COUNT purpose since the data is already unique after implementing DISTINCT. If the SELECT has 3 columns listed then SELECT DISTINCT will fetch unique row for those 3 column values only. The count for the first query is greater than the second query. I changed it to mydate in the queries. Hive will automatically separate skewed values into different files and take this into consideration during searches so that it can skip or include whole files if possible; thus… Jan 6, 2024 · Before diving into multiple columns, let’s grasp the basic concept of the SELECT DISTINCT command. Jul 17, 2020 · The Column personalemailtrim to be DISTINCT The column Occurrences must be over Count >1 Order by the column personalemailtrim My Query so far build is wrong in many levels, Group by cant with DISTINCT and also using Count (*) doesnt give me any results with Group my etc. png Count distinct doesn't always give me the right answer. You cannot use the column id because there are potentially different values. Dec 6, 2019 · How do I select two distinct columns? Select with distinct on all columns of the first query. I've attached two different queries that should both result in 7 unique items purchased. I know the following code works in Microsoft SQL Server. The DISTINCT can comes only once in a given select statement. We may encounter a very special behavior when Hive deals with aggregation across columns with a NULL value 1 Answers Yes, Hive does support distinct on multiple columns. apache. The defined values override any other configuration and session property settings. -- Returns the unique values from one column. Nov 29, 2023 · distinct() eliminates duplicate records (matching all columns of a Row) from DataFrame, count () returns the count of records on DataFrame. HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) HIVE-1459 wildcards in UDF/UDAF should expand to all columns (rather than no columns) Sep 7, 2023 · In our example, the group is defined by the values in the column customer_id. In the end I want a table which shows me how many user have more than to different characteristics. It is often used with the GROUP BY clause to return the count of rows for each group. Hive will automatically separate skewed values into different files a… Dec 27, 2012 · I have multiple columns in my distinct (example count (distinct tag, date)). This is listed in the documentation, but it's a bit ambiguously worded when there are multiple fields. However, it is ironic that Postgres has a similar performance issue with COUNT(DISTINCT), although I think the underlying reason is a little bit different. Sep 24, 2009 · If you are trying to improve performance, you could try creating a persisted computed column on either a hash or concatenated value of the two columns. If not is there a way to achieve this? Apr 6, 2025 · In this guide, we'll explore how to achieve a distinct count horizontally across multiple columns using Hive SQL clear and concisely. Note: Most of these functions ignore NULL values. 0 (HIVE-9194). . It means that the query will use the combination of values in all columns to evaluate the distinction. -- NULL is included in the set of values if any rows have a NULL in this column. Public signup for this instance is . May 20, 2025 · Hive’s aggregate functions operate on columns of various data types, including numeric, string, and date types, and are often combined with other Hive features like joins or partitioning. How do I count a column in SQL query? Query to count the number of columns in a table: select count (*) from user_tab_columns where table_name = ‘tablename’; Replace tablename with the name of the table whose total number of columns you want returned. As a result, the distribution is skewed. For example, the following is possible because count (DISTINCT) and sum (DISTINCT) specify the same column: INSERT OVERWRITE TABLE pv_gender_agg Hi Gopal, Thanks for all the information and suggestion. You did: select col1, count (distinct col2, col3) from dummy group by col1 I think the correct syntax is: select col1, count (distinct (col2, col3)) from dummy group by col1 You can use DISTINCT on a single column to fetch unique values from that column or on multiple columns to get distinct combinations of values. However, we need to know the syntax of HiveQL group by query to implement it. Count () function and select with distinct on multiple columns. The dataset… Obviously, COUNT(DISTINCT) with multiple columns counts unique combinations of the specified columns' values. It would be a good idea to maintain some compatibility for the existing interface - so, can we add another method to UDAFResolver, which has the new API - and a common class which invokes the default implementation, that would be better. 0 and later (see HIVE-9534) Distinct is supported for aggregation functions including SUM, COUNT and AVG, which aggregate over the distinct values within each partition. Go to our to request an account. Please see the corresponding JIRA for workarounds: https://issues. Suppose you had a table like so, with 2 columns and only 2 rows of data: SELECT * FROM table1; colA colB A B A Sep 10, 2025 · A quick tutorial on using COUNT DISTINCT on multiple columns in SQL. Feb 17, 2017 · I have a huge paragraph hive query code like this below: select count (distinct case when click_day between $ {hiveconf:dt_180} and $ {hiveconf:dt_end} and recommend_flag=1 then productid else nul DISTINCT Clause in Aggregate Functions When the DISTINCT clause is provided, only distinct values are considered in the computation of the aggregate. And I want to get the distinct count across the three columns. Jun 8, 2021 · How do I get distinct values of all columns in hive? SELECT DISTINCT colA, colB FROM table1; Which of the following results would be returned for the query above? The thinking for this possibility is that while the values are not distinct on colA , the entire returned row is unique, or distinct, when both columns are considered. Sep 10, 2008 · 30 The problem with your query is that when using a GROUP BY clause (which you essentially do by using distinct) you can only use columns that you group by or aggregate functions. This came up on the Hive mailing list and I’m putting it here as a reminder to try it out. [jira] Commented: (HIVE-287) count distinct on m Ashish Thusoo (JIRA) [jira] Commented: (HIVE-287) count distinct on mJohn Sichi (JIRA) Arvind Prabhakar commented on HIVE-287: --------------------------------------- I think keeping two different interfaces for UDAFs will lead to confusion in the long run. If you want to select distinct values of some columns in the select list, you should use the GROUP BY clause. Jun 8, 2021 · The thinking for this possibility is that while the values are not distinct on colA , the entire returned row is unique, or distinct, when both columns are considered. DROP TABLE IF EXISTS Jul 21, 2017 · count distinct values from multiple column hive Asked 7 years, 7 months ago Modified 7 years, 7 months ago Viewed 1k times Jun 9, 2020 · Hive Select Count and Count Distinct Syntax: count (*) Syntax: count (expr) Syntax: count (DISTINCT expr [, expr…]) Return: BIGINT. The DISTINCT keyword returns unique records from the table. SELECT DISTINCT c_birth_country FROM customer; -- Returns the unique combinations of values from multiple columns. count (distinct) Deduplication statistics for some fields, for example: number of statistics users (statistic deduplicated user ID) count (distinct userId) Optimization reason: Because DISTINCT is int Mar 31, 2016 · Im trying to select distinct values from each column inside a given table. Mar 13, 2014 · Hi does Hive support distinct on multiple columns. How do I count distinct values in a column in HIVE? DISTINCT keyword is used in SELECT statement in HIVE to fetch only unique rows. This allows strict validation to be performed. It is quite reasonable that your table has only 151,616 distinct values in the column a, but multiple rows with the same value in the column a have different values in other columns. gender; Multiple aggregations can be done at the same time, however, no two aggregations can have different DISTINCT columns. oxx cxrx wmwbr kfsvk yitj ihm vjseg qonsv orgaxlw qtidt