Does sql distinct apply to all columns

Does SQL distinct apply to all columns ? What are the capabilities of select SQL statements? What is COUNT function in SQL database? How does the default constraint work in SQL ? Read an example of an SQL case expression from our SQL expert Rudy Limeback. DISTINCT applies to all columns in the result. I need all columns in a table but two columns must be distinct.

I used this code but It check all columns , but I only need two of them will be distinct. Does select distinct apply to all columns ? How to delete stored procedures in SQL ? Is foreign key use in SQL join? Ask Question Asked years ago. I need to query an SQL database to find all distinct values of one column and I need an arbitrary value from another column.

You can select distinct for more than one column, however, the distinct refers to all the columns in the select list. In your example, if you leave out the parens, it should work fine. If you need to select distinct values of only some columns , then you need to concatenate them as Brad suggested. Example - Finding Unique Values in Multiple Columns.

Distinct is ran on the selected columns after records are found ( all joins are evaluated and columns are retrieved), so when using distinct it should not be possible to get duplicates (across all columns ), no matter what you do. If the selected columns result in duplicate rows, they will be removed. Consider the below SQL on AdventureWorks.

SELECT one column, with multiple columns returned where other columns are same, mysql query. Select multiple columns from access. There have been numerous times I have wanted to do this, but have not found an easy way. In this instance I am selecting four columns and just want to distinct on the first column because the data of the four is different enough it returns duplicates of the first column.

Basically I am wanting to be distinct on one row, but view different rows. Can anyone show me the sql statement to do this. Update: Tested all queries in SQLfiddle with 100K rows (and separate cases, one with few (25) distinct values and another with lots (around 25K values).

I think it would be most efficient if there is a separate index on each of the four columns It would be efficient with a separate index on each of the four columns , if Postgres had. The following will make all three columns distinct. In real life, very few queries are this simple.

I want only the Job_ID column to be distinct. SQL Server will thank you for it. I have a reporting requirement and it has so many summarized columns I retrieve.

All my summaries are taken as a derived column, hence I cannot use a group by to retrieve this column. Is there any reason that sql doesnt support a distinct on. The primary key ensures that the table has no duplicate rows. However, when you use the SELECT statement to query a portion of the columns in a table, you may get duplicates.

Usually, GROUP BY can solve this, but it might not be the most efficient metho or fail to accomplish other issues with the requirements in the query. What do you expect as the final result if you wanted to apply distinct to the first column? Any solution will likely be specific to your dbms. Question: I need to display distinct records of each column within a single table. How do you write a SQL to select each distinct column within a table without using a function?

Answer: By Laurent Schneider, from his book ? Advanced Oracle SQL Programming? In this query we start by selecting the distinct values for all columns. I have a query which uses three lookup tables to get all the information I need. We can count during aggregation using GROUP BY to make distinct when needed after the select statement to show the data with counts. Remember that you must include the columns that are before the count in GROUP BY: SELECT column, COUNT(column).

But as ALL is the default keywor so we usually do not include ALL in our queries.