What is distinct clause in SQL?

Description. The SQL DISTINCT clause is used to remove duplicates from the result set of a SELECT statement.

Why distinct clause is used in SQL?

The distinct keyword is used in conjunction with select keyword. It is helpful when there is a need of avoiding duplicate values present in any specific columns/table. When we use distinct keyword only the unique values are fetched.

How do I display unique records in SQL?

SQL SELECT DISTINCT Explanation 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.

How do you write a distinct case in SQL?

Explanation : Since the DISTINCT keyword works on a complete record, we need to write conditions “x <30” and “x>=30” separately in CASE WHEN. The COALESCE function tells SAS to replace missing values with 0 and then sum the returned values of both the conditions.

What are the clauses in SQL?

Types of SQL Clause

• SELECT Clause in SQL. Select clause is used to query the database and display the output.
• UPDATE Clause in SQL. Allows us to update the records present in our database.
• INSERT Clause in SQL.
• DELETE Clause in SQL.
• UNION Clause in SQL.
• GROUP By Clause in SQL.
• ORDER By Clause in SQL.
• HAVING Clause in SQL.

What is the difference between WHERE and having clause?

A HAVING clause is like a WHERE clause, but applies only to groups as a whole (that is, to the rows in the result set representing groups), whereas the WHERE clause applies to individual rows. A query can contain both a WHERE clause and a HAVING clause. The HAVING clause is then applied to the rows in the result set.

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.

Can we use distinct in case statement?

In general whenever we have to use ‘distinct’ clause along with case statement, it always resides outside the case statement unless we are using a sub-query in the case statement. If we put ‘distinct’ clause inside case statement, we will get ora-00936, missing expression error.

What is the difference between unique and distinct in SQL?

The main difference between Unique and Distinct in SQL is that Unique helps to ensure that all the values in a column are different while Distinct helps to remove all the duplicate records when retrieving the records from a table.

What are the 2 required clauses in SQL?

SQL clauses

• CONSTRAINT clause.
• FOR UPDATE clause.
• FROM clause.
• GROUP BY clause.
• HAVING clause.
• ORDER BY clause.
• The result offset and fetch first clauses.
• USING clause.

How to select distinct SQL?

How to Use SQL SELECT DISTINCT Statement to Retrieve Unique Data Using the DISTINCT clause with the SELECT statement is the simple method. You just need to put the DISTINCT clause after the SELECT statement. Then after you have to specify the column name from which you want to fetch only the distinct values and not the duplicate values.

What is the difference between distinct and unique in SQL?

The main difference between Unique and Distinct in SQL is that Unique helps to ensure that all the values in a column are different while Distinct helps to remove all the duplicate records when retrieving the records from a table.

What is distinct in SQL language?

The SQL DISTINCT keyword is used in conjunction with the SELECT statement to eliminate all the duplicate records and fetching only unique records. There may be a situation when you have multiple duplicate records in a table. While fetching such records, it makes more sense to fetch only those unique records instead of fetching duplicate records.

What is SELECT DISTINCT in MySQL?

The MySQL Select Distinct behaviour is inherits from the Group By. If you use the Group By Clause without any Aggregate Function then it will act as the Distinct keyword. And the Only difference between them is: Group By will sort the Data first, and then perform grouping. Distinct keyword does not perform any sorting.