Can we use distinct with GROUP BY in SQL?

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.

Can I use distinct with GROUP BY?

Well, GROUP BY and DISTINCT have their own use. GROUP BY cannot replace DISTINCT in some situations and DISTINCT cannot take place of GROUP BY. It is as per your choice and situation how you are optimizing both of them and choosing where to use GROUP BY and DISTINCT.

Can I use distinct in HAVING clause?

The HAVING clause generally complements a GROUP BY clause. If you omit the GROUP BY clause, the HAVING clause applies to all rows that satisfy the query, and all rows in the table make up a single group. The condition in the HAVING clause cannot include a DISTINCT or UNIQUE aggregate expression.

Is distinct faster or GROUP BY?

DISTINCT creates a temporary table and uses it for storing duplicates. GROUP BY does the same, but sortes the distinct results afterwards. is faster, if you don’t have an index on profession .

What can I use instead of GROUP BY?

select , from , where , union , intersect , minus , distinct , count , and , or , as , between .

Is there any difference between GROUP BY and distinct?

GROUP BY lets you use aggregate functions, like AVG , MAX , MIN , SUM , and COUNT . On the other hand DISTINCT just removes duplicates. This will give you one row per department, containing the department name and the sum of all of the amount values in all rows for that department.

Is GROUP BY more efficient than distinct?

In MySQL, DISTINCT seems a bit faster than GROUP BY if theField is not indexed. DISTINCT only eliminate duplicate rows but GROUP BY seems to sort them in addition.

Is distinct faster than GROUP BY SQL Server?

DISTINCT is used to filter unique records out of all records in the table. It removes the duplicate rows. SELECT DISTINCT will always be the same, or faster than a GROUP BY.

Can you use distinct twice in SQL?

No you can’t use that, it will throw an error, but there are other alternatives where you can get your desired results.

What is the use of distinct clause in SQL give an example?

Example: Finding Unique Values in Multiple Column The SQL DISTINCT clause is used to remove the duplicate records from many fields in the SELECT statement. Enter the SQL statement: SELECT DISTINCT city, state. FROM suppliers.

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.

Is it good to use distinct in SQL?

SQL DISTINCT clause is used to remove the duplicates columns from the result set. The distinct keyword is used with select keyword in conjunction. It is helpful when we avoid duplicate values present in the specific columns/tables. The unique values are fetched when we use the distinct keyword.

What is the difference between select and group by in SQL?

GROUP BY Clause is utilized with the SELECT statement. GROUP BY aggregates the results on the basis of selected column: COUNT, MAX, MIN, SUM, AVG, etc. GROUP BY returns only one result per group of data. GROUP BY Clause always follows the WHERE Clause.

What is the difference between group by and having clause in MySQL?

The GROUP BY clause groups the returned record set by one or more columns. You specify which columns the result set is grouped by. The above query selects all records from the users database table, then groups them by the address field. MySQL HAVING Clause is used with GROUP BY clause. It always returns the rows where condition is TRUE.

What is the difference between order by and GROUP BY clause?

GROUP BY Clause is utilized with the SELECT statement. GROUP BY aggregates the results on the basis of selected column: COUNT, MAX, MIN, SUM, AVG, etc. GROUP BY returns only one result per group of data. GROUP BY Clause always follows the WHERE Clause. GROUP BY Clause always precedes the ORDER BY Clause ( ).

What is the difference between where clause and having clause in SQL?

Where Clause applied first and then Having Clause. WHERE Clause restricts records before GROUP BY Clause, whereas HAVING Clause restricts groups after GROUP BY Clause are performed. WHERE Clause can be utilized with SELECT, UPDATE, DELETE, and INSERT, whereas HAVING can be utilized only with SELECT statement.