Contents
How to select distinct on just one column?
How can I SELECT DISTINCT on just one column? The simplest solution would be to use a subquery for finding the minimum ID matching your query. In the subquery you use GROUP BY instead of DISTINCT: SELECT t.* FROM TestData t INNER JOIN (SELECT MIN (ID) as MinID FROM TestData WHERE SKU LIKE ‘FOO-%’ ) dt ON t.ID=dt.MinID
Why does select distinct return only unique values?
Adding the DISTINCT keyword to a SELECT query causes it to return only unique values for the specified column list so that duplicate rows are removed from the result set. Since DISTINCT operates on all of the fields in SELECT’s column list, it can’t be applied to an individual field that are part of a larger group.
When to use distinct and group by in SQL?
Does anyone know of any situations where both DISTINCT and GROUP BY need to be used, to get any specific desired results? You would use this to return different levels of aggregation returned in a single row. The use case would be for when a single grouping would not suffice all of the aggregates needed.
Can you select columns by order in MySQL?
Keep in mind when using the group by and order by that MySQL is the ONLY database that allows for columns to be used in the group by and/or order by piece that are not part of the select statement. That will not fly in other databases like Postgres, Oracle, MSSQL, etc.
Is there a primary key for SELECT DISTINCT values?
There is no primary key in this. I have succeeded with the followin queries Interestingly enough I tried both of these in LinqPad and the variant using group from Dmitry Gribkov by appears to be quicker. (also the final distinct is not required as the result is already distinct. Thanks for contributing an answer to Stack Overflow!
How to select all unique values in a column?
How do I get a full list of categories (All the unique values in the Category Column)? public IEnumerable GetProductsByCategory (string category) { return repository.GetAllProducts ().Where ( p => string.Equals (p.Category, category, StringComparison.OrdinalIgnoreCase)); }
When to use distinct and group by in Excel?
In other words, when several rows contain the same email, I want the results to include only one of those rows (preferably the last one). Duplicates in other columns should be allowed. Clauses like DISTINCT and GROUP BY appear to work on entire rows.