Question: How Do You Select Distinct Rows Without Using Distinct?

How do I select distinct in hive?

DISTINCT keyword is used in SELECT statement in HIVE to fetch only unique rows.

The row does not mean entire row in the table but it means “row” as per column listed in the SELECT statement.

If the SELECT has 3 columns listed then SELECT DISTINCT will fetch unique row for those 3 column values only..

How can I delete duplicate rows?

Remove duplicate valuesSelect the range of cells that has duplicate values you want to remove. Tip: Remove any outlines or subtotals from your data before trying to remove duplicates.Click Data > Remove Duplicates, and then Under Columns, check or uncheck the columns where you want to remove the duplicates. … Click OK.

How do you retrieve unique rows from database without using distinct or unique keyword?

SQL | Remove Duplicates without DistinctRemove Duplicates Using Row_Number. 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 = 1.2.Remove Duplicates using self Join. … Remove Duplicates using group By.

How do you select distinct?

To do this, you use the SELECT DISTINCT clause as follows: SELECT DISTINCT column_name FROM table_name; The query returns only distinct values in the specified column. In other words, it removes the duplicate values in the column from the result set.

How do I remove duplicates in select query?

The go to solution for removing duplicate rows from your result sets is to include the distinct keyword in your select statement. It tells the query engine to remove duplicates to produce a result set in which every row is unique. The group by clause can also be used to remove duplicates.

How do I find unique rows in SQL?

SQL SELECT DISTINCT Statement SELECT DISTINCT returns only distinct (i.e. different) values. The DISTINCT keyword eliminates duplicate records from the results. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc. It operates on a single column.

How do I filter duplicates in SQL query?

SELECT [ALL | DISTINCT] columns FROM table; If a table has a properly defined primary key, SELECT DISTINCT * FROM table; and SELECT * FROM table; return identical results because all rows are unique. For DISTINCT operations, the DBMS performs an internal sort to identify and remove duplicate rows.

What does select distinct do?

The SELECT DISTINCT statement is used to return only distinct (different) values. Inside a table, a column often contains many duplicate values; and sometimes you only want to list the different (distinct) values.

Does Count distinct count nulls?

COUNT(expression) like all aggregate functions, can take an optional DISTINCT clause. The DISTINCT clause counts only those columns having distinct (unique) values. COUNT DISTINCT does not count NULL as a distinct value. … The ALL keyword counts all non-NULL values, including all duplicates.

Can we use distinct in where clause?

Within the WHERE clause lies many possibilities for modifying your SQL statement. Among these possibilities are the EXISTS, UNIQUE, DISTINCT, and OVERLAPS predicates. Here are some examples of how to use these in your SQL statements.

How do I eliminate duplicate rows in SQL?

RANK function to SQL delete duplicate rows We can use the SQL RANK function to remove the duplicate rows as well. SQL RANK function gives unique row ID for each row irrespective of the duplicate row. In the following query, we use a RANK function with the PARTITION BY clause.

How do I limit the number of rows in hive?

The LIMIT clause can be used to constrain the number of rows returned by the SELECT statement. LIMIT takes one or two numeric arguments, which must both be non-negative integer constants. The first argument specifies the offset of the first row to return (as of Hive 2.0.

How remove duplicates in SQL with distinct?

To remove duplicates from a result set, you use the DISTINCT operator in the SELECT clause as follows: SELECT DISTINCT column1, column2, … FROM table1; If you use one column after the DISTINCT operator, the database system uses that column to evaluate duplicate.

How do you count distinct records 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;

Does Hive support subqueries?

Hive supports subqueries only in the FROM clause (through Hive 0.12). The subquery has to be given a name because every table in a FROM clause must have a name. … The columns in the subquery select list are available in the outer query just like columns of a table. The subquery can also be a query expression with UNION.