How To Remove Duplicates In Hive Query

I am trying to learn about deleting duplicate records from a Hive table. The Group By clause groups data as per the defined columns and we can use the COUNT function to check the occurrence of a row.

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The following Delete statement deletes the rows using the Rowid.

How to remove duplicates in hive query. Here first create a temp table and insert distinct rows in the temp table. WITH CTE Col1 Col2 Col3 DuplicateCount AS SELECT Col1 Col2 Col3 ROW_NUMBER OVER PARTITION BY Col1 Col2 Col3 ORDER BY Col1 AS DuplicateCount FROM MyTable SELECT from CTE Where DuplicateCount 1 2Remove Duplicates using self Join. Double-click the asterisk to add all of the table fields to the query designer.

That means that Hive allows duplicates in Primary Keys. This way you will get list of duplicated rows. To solve your issue you should do something like this.

To remove duplicate rows using this command. Compute hash of row and group by on hash pick first record of each. Then click on the New button in the toolbar to obtain the dialog box shown in Figure B.

Insert overwrite table duplicate_test select distinct from duplicate_test. Before deleting the rows you should verify that the entire row is duplicate. Id Name Technology 1 Abcd Hadoop 2 Efgh Java 3 Ijkl MainFrames 2 Efgh Java We have options like Distinct to use in a select query but a select query just retrieves data from the table.

May 15 2018 1 min read. Insert the temp table contents which has the unique row into the original table. Hi Dmitry I try your build with cassandra 123hive 090 I have a issue that I always get the duplicated records in Hive.

Data types of the column that you are trying to combine should match. Now we see how to delete the duplicate records from the products table in different ways. A UNION set operation removes duplicate rows from the result set.

If the GROUP BY query returns multiple rows the set rowcount query will have to be run once for each of these rows. Remove Duplicates Using Row_Number. To remove duplicate values you can use insert overwrite table in Hive using the DISTINCT keyword while selecting from the original table.

For example consider following example to insert overwrite the hive table from original table using the DISTINCT keyword in SELECT clause. Select distinct from. Begin by clicking Queries under Objects in the Database Window.

I have a huge history data set in HDFS on top of which i want to remove duplicates to begin with and also the daily ingested data have to be compared with the history to remove duplicates plus the daily data may have duplicates within itself as well. And then use this. There are two methods here to delete duplicates they are using group by and Rank Using group by and min.

CREATE COLUMN FAMILY users WITH comparator UTF8Type AND key_validation_classUTF8Typ. Hive UNION Set Operator Example. Select any cell within the data set that you want to remove the duplicates from and click on the Remove Duplicatesbutton.

A record is duplicate if there are occurrences of the same entire record multiple times. The DISTINCT keyword returns unique records from the table. Then delete the duplicates with delete from dbo.

Select Find Duplicates Query. The Hive UNION set operation is different from JOIN which combine the columns from two tables. OriginaltableProduct_Name and Date dbo.

Add an identity column to the duplicate table as a serial number that acts as a row unique identifier auto incremental ascending order. Add the fields that you will use to identify the records for deletion. Sometimes we have a requirement to remove duplicate events from the hive.

Remove Duplicate Rows Using the Excel Remove Duplicates Command The Remove Duplicatescommand is located in the Data Tools group within the Datatab of the Excel ribbon. SQL delete duplicate Rows using Group By and having clause In this method we use the SQL GROUP BY clause to identify the duplicate rows. We can use distinct to view unique records.

Using temp table and Distinct. Answered Jul 11 2019 by Bhuvan. If the keys in 2 records are the same then they are duplicates.

Select every column count from mytable group by every column having count 1. Dedupe De Duplicate data in HIVE. Group rows on PKor unique identifier for each row and use partition over to compute rownumbers and pick first row from each group.

Originaltable where EXISTS SELECT product_Name Date CustomerID from Temp WHERE Product_Name dbo. Each time it is run set rowcount to n-1 the number of duplicates of the particular PK value. Click the Create tab Query Design and double-click the table from which you want to delete records.

Remove Duplicates From Hive Table Using Group By Stack Overflow