Can we use distinct on two columns in SQL?

How do I use distinct two columns in SQL?

Contents:

1. Sample Select statement.
2. Select with distinct on two columns.
3. Select with distinct on three columns.
4. Select with distinct on all columns of the first query.
5. Select with distinct on multiple columns and order by clause.
6. Count() function and select with distinct on multiple columns.

Can we apply distinct two columns?

Yes, the DISTINCT clause can be applied to any valid SELECT query. It is important to note that DISTINCT will filter out all rows that are not unique in terms of all selected columns.

Does distinct apply to all columns SQL?

The DISTINCT keyword is applied to all columns. It means that the query will use the combination of values in all columns to evaluate the distinction. If you want to select distinct values of some columns in the select list, you should use the GROUP BY clause.

Does distinct apply to all columns?

Yes, DISTINCT works on all combinations of column values for all columns in the SELECT clause.

Can we use distinct on multiple columns in Oracle?

C) Oracle SELECT DISTINCT and NULL

The DISTINCT treats NULL values to be duplicates of each other. … As you can see, only one NULL values is returned. Note that if you want to apply the DISTINCT to some columns, while skipping other columns, you should use the GROUP BY clause instead.

How do I count different columns on the same table?

SELECT CompanyName, TotalOpenClaims = COUNT(CASE WHEN StatusID = 1 THEN ClaimID END), TotalClosedClaims = COUNT(CASE WHEN StatusID = 2 THEN ClaimID END), TotalReOpenedClaims = COUNT(CASE WHEN StatusID = 3 THEN ClaimID END), TotalPendingClaims = COUNT(CASE WHEN StatusID = 4 THEN ClaimID END) FROM dbo.

Can we use distinct in where clause?

WHERE conditions: The conditions may meet for the records which are selected and it is optional. Note: When one expression is provided in the DISTINCT clause then the query will return the unique values of the expressions.

How do I select multiple columns with only one group?

2 Answers

1. Add the additional columns to the GROUP BY clause: GROUP BY Rls.RoleName, Pro.[FirstName], Pro.[LastName]
2. Add some aggregate function on the relevant columns: SELECT Rls.RoleName, MAX(Pro.[FirstName]), MAX(Pro.[LastName])

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 eliminate duplicate rows in SQL query without distinct?

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.

Does distinct have to be first?

Because the DISTINCT keyword applies to the entire result set, and not just one column, the DISTINCT must go at the start of the query, just after SELECT: SELECT DISTINCT col1, col2, col3 FROM table… I’ll show an example of this later in the guide.