SELECT DISTINCT returns only unique (i.e. distinct) values. SELECT DISTINCT eliminates duplicate values from the results. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc. DISTINCT operates on a single column.
How do you SELECT unique records from a table?
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.
How can I get distinct values from a column in SQL?
How to use distinct in SQL?
- SELECT DISTINCT returns only distinct (different) values.
- DISTINCT eliminates duplicate records from the table.
- DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc.
- DISTINCT operates on a single column.
- Multiple columns are not supported for DISTINCT.
How do I return unique rows in SQL?
The SQL Distinct command can be used in the SELECT statement to ensure that the query returns only distinct (unique) rows. When the query is selecting the rows it discards any row which is a duplicate of any other row already selected by the query.
How does SELECT distinct work?
When only one expression is provided in the DISTINCT clause, the query will return the unique values for that expression. When more than one expression is provided in the DISTINCT clause, the query will retrieve unique combinations for the expressions listed. In SQL, the DISTINCT clause doesn’t ignore NULL values.
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.
How do you select unique records from a table without using distinct?
Below are alternate solutions :
- 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.
- Remove Duplicates using group By.
What is the use of distinct keyword?
The DISTINCT keyword is used to fetch distinct records from a database table. The DISTINCT clause is basically used to remove duplicates from the result set of a SELECT statement and only selects DIFFERENT values.
Can we use distinct and count together in SQL?
Yes, you can use COUNT() and DISTINCT together to display the count of only distinct rows. SELECT COUNT(DISTINCT yourColumnName) AS anyVariableName FROM yourTableName; … If you do not use DISTINCT, then COUNT() function gives the count of all rows.
How does unique work in SQL?
A unique key is a set of one or more than one fields/columns of a table that uniquely identify a record in a database table. You can say that it is little like primary key but it can accept only one null value and it cannot have duplicate values.
How do I get unique values in SOQL?
How to find the distinct values of a particular field in a SObject using SOQL Query? Its possible by using the GROUP BY Clause in an SOQL Query. For example: Select Name from Account GROUP BY Name – This will give all the distinct values for the Account Name field from Account Object.
How do I select distinct rows in mysql?
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.
What is a distinct value?
In math, the term distinct number is used to refer to a number in a set that is not equal to another number. … For example, the equation 4 = x^2 has two distinct values for x, as both -2^2 and 2^2 equal 4.
Can we use distinct in group by?
Distinct is used to find unique/distinct records where as a group by is used to group a selected set of rows into summary rows by one or more columns or an expression. The functional difference is thus obvious. The group by can also be used to find distinct values as shown in below query.
What is difference between unique and distinct in SQL?
The UNIQUE keyword in SQL plays the role of a database constraint; it ensures there are no duplicate values stored in a particular column or a set of columns. On the other hand, the DISTINCT keyword is used in the SELECT statement to fetch distinct rows from a table.