GROUP BY In SQL Server

Question

I want to know why we use GROUP BY In SQL server ? Thank you.

Akkiraju Ivaturi · Answer

Group by provides you to select subset of data grouped together. Otherwise, normal select statement orders the data based on the order by clause or how the data is stored in database.

Satyapriya Nayak · Answer

http://www.sqlteam.com/article/how-to-use-group-by-in-sql-server, http://www.w3schools.com/sql/sql_groupby.asp

Rahul Bhatt · Answer

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Jignesh Trivedi · Answer

hi, Grouping records is the process of combining like SELECT columns together. Once combined, Aggregate functions such as SUM and AVERAGE can be performed on the set. GROUP BY should be used to apply aggregate operators to each group. SELECT Employee, Rank FROM Employees GROUP BY Employee, Rank http://msdn.microsoft.com/en-us/library/ms177673.aspx hope this will help you.

Hemant Srivastava · Answer

Following example will show why we use "GROUP BY" SQL GROUP BY Example We have the following "Orders" table: O_IdOrderDateOrderPriceCustomer 1 2008/11/12 1000 Hansen 2 2008/10/23 1600 Nilsen 3 2008/09/02 700 Hansen 4 2008/09/03 300 Hansen 5 2008/08/30 2000 Jensen 6 2008/10/04 100 Nilsen Now we want to find the total sum (total order) of each customer. We will have to use the GROUP BY statement to group the customers. We use the following SQL statement: SELECT Customer,SUM(OrderPrice) FROM Orders GROUP BY Customer The result-set will look like this: CustomerSUM(OrderPrice) Hansen 2000 Nilsen 1700 Jensen 2000 Nice! Isn't it? :) Let's see what happens if we omit the GROUP BY statement: SELECT Customer,SUM(OrderPrice) FROM Orders The result-set will look like this: CustomerSUM(OrderPrice) Hansen 5700 Nilsen 5700 Hansen 5700 Hansen 5700 Jensen 5700 Nilsen 5700 The result-set above is not what we wanted. If it helps you, pls make it accepted. Thanks