Frequently Asked Questions (FAQ) - SQL SELECT with DISTINCT on multiple columns 1.What is the purpose of using DISTINCT on multiple columns in SQL? DISTINCT on multiple columns eliminates rows where all selected fields are identical, ensuring unique combinations of the specified columns in the resu...
I have a dataset that is filled from an SQL table. It has four columns (col_1, col_2, col_3, col_4) I want to create another datatable/dataset wihch contains only two columns (col_1, and col_2) with distinct records from the first dataset with LINQ in VB.NET. Somthing like ...
You can also get SQL to do math tricks for you. It can do some pretty complicated arithmetic if you allow it to do so. For today, I’ll show you how to multiply two numbers, but you can just as easily add, subtract, or divide. Later we’ll make it more involved so you can rel...
When distinct cannot return unique row when all columns combination is not unique then we can use distinct on clause which will give first row from that set of duplicate rows.The column which we are specifying in DISTINCT ON <col_name> should also be present in the ORDER BY clause; otherwi...
1. Basic Use of DISTINCT on Multiple Columns Code: -- Retrieve unique combinations of first_name and last_name SELECT DISTINCT first_name, last_name -- Get distinct pairs of first and last names FROM employees; -- From the employees table ...
SELECT DISTINCT Company, Country FROM Cars; And the result looks like this: When you have more than one column in your SQL DISTINCT statement, the SQL interpreter selects all unique combinations between those columns. In our Cars table we have two entries for Toyota (Company column) and those...
Is a shorthand for aUSINGlist that mentions all columns in the two tables that have the same names. from item Specifies the name of the query source object connected. WHERE clause Forms an expression for row selection to narrow down the query range ofSELECT.conditionindicates any expression tha...
This example uses two correlated subqueries to find the names of employees who sold a particular product. SQL USEAdventureWorks2022; GOSELECTDISTINCTpp.LastName, pp.FirstNameFROMPerson.Person ppINNERJOINHumanResources.Employee eONe.BusinessEntityID = pp.BusinessEntityIDWHEREpp.BusinessEntityIDIN(SELECT...
Aclause(子句)is a part of a SQL statement(Select语句的一个组成部分) ——for example,SELECT emplovee_id, last_name, and so on Astatement(语句)is a combination(组合)of two or more clauses(Select语句是两个或者多个子句的组合) ——for example,SELECT * FROM employees(SELECT *叫一个子句,FR...
This example uses two correlated subqueries to find the names of employees who sold a particular product. SQL Copy USE AdventureWorks2022; GO SELECT DISTINCT pp.LastName, pp.FirstName FROM Person.Person pp INNER JOIN HumanResources.Employee e ON e.BusinessEntityID = pp.BusinessEntityID WHERE ...