How can I get distinct records in SQL JOIN?

How can I get distinct values in SQL JOIN?

You can use CTE to get the distinct values of the second table, and then join that with the first table. You also need to get the distinct values based on LastName column. You do this with a Row_Number() partitioned by the LastName, and sorted by the FirstName.

How do I get unique results in SQL?

The unique values are fetched when we use the distinct keyword.

  1. SELECT DISTINCT returns only distinct (different) values.
  2. DISTINCT eliminates duplicate records from the table.
  3. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc.
  4. DISTINCT operates on a single column.

How can I get unique records without using distinct in SQL?

Below are alternate solutions :

  1. Remove 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 group By.

How do I get distinct values in SQL Developer?

Introduction to Oracle SELECT DISTINCT statement

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SELECT DISTINCT column_1 FROM table; In this statement, the values in the column_1 of the table are compared to determine the duplicates. In this syntax, the combination of values in the column_1 , column_2 , and column_3 are used to determine the uniqueness of the data.

What does distinct do in SQL?

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.

How do I find duplicate rows in SQL?

How to Find Duplicate Values in SQL

  1. Using the GROUP BY clause to group all rows by the target column(s) – i.e. the column(s) you want to check for duplicate values on.
  2. Using the COUNT function in the HAVING clause to check if any of the groups have more than 1 entry; those would be the duplicate values.

How do you write not in SQL?

Overview. The SQL Server NOT IN operator is used to replace a group of arguments using the <> (or !=) operator that are combined with an AND. It can make code easier to read and understand for SELECT, UPDATE or DELETE SQL commands.

Which SQL keyword is used to retrieve a maximum value?

MAX() is the SQL keyword is used to retrieve the maximum value in the selected column.

What is difference between unique and distinct?

The main difference between unique and distinct is that UNIQUE is a constraint that is used on the input of data and ensures data integrity. While DISTINCT keyword is used when we want to query our results or in other words, output the data.

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Why distinct is bad in SQL?

Well, improper use of “distinct” not only hides the real problem (duplicate entries in the tables, lack of condition in the on clause) as discussed above but also degrades query performance. … This will bring the IO Cost (logical reads) of the query goes up significantly.

What we can use instead of distinct in SQL?

6 Answers. GROUP BY is intended for aggregate function use; DISTINCT just removes duplicates (based on all column values matching on a per row basis) from visibility. If TABLE2 allows duplicate values associated to TABLE1 records, you have to use either option.

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