Can we use distinct in HAVING?
Can we use distinct in HAVING?
using Distinct with a Group BY is redudant, yes. But it doesnt solve the root problem. The root problem is that the HAVING clause counts the total number before the GROUP BY or the DISTINCT is operated on. Thus removing the DISTINCT will still cause an incorrect count.
Can I count distinct in SQL?
The correct syntax for using COUNT(DISTINCT) is: SELECT COUNT(DISTINCT Column1) FROM Table; The distinct count will be based off the column in parenthesis. The result set should only be one row, an integer/number of the column you’re counting distinct values of.
How do I find unique rows in SQL?
SELECT DISTINCT returns only unique values (without duplicates). DISTINCT operates on a single column. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc.
Is distinct same as unique?
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.
What is unique key 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.
What is the difference between where and having in SQL?
The key difference between where and having clause in SQL is that where clause is used to filter records before a grouping or an aggregation occurs while having clause is used to filter records after a grouping, or an aggregation occurs.
How to use distinct in SQL?
Example: Our database has a table named books with data in the columns author_firstname,author_lastname,and book_title.
What does SQL SELECT DISTINCT mean?
Distinct in SQL is a commonly used keyword meant to retrieve values from a table and eliminate duplicates. The SQL SELECT DISTINCT statement will only retrieve unique values from the selected table.
Where vs having in SQL?
The difference between the having and where clause in SQL is that the where clause cannot be used with aggregates, but the having clause can. The where clause works on row’s data, not on aggregated data. Let us consider below table ‘Marks’.
