Group By and Having Clause

Question

What is Difference between Group by and Having Clause and where and Why we use that ?? please explain with Sql Query.

Tanlin · Answer

GROUP BY is used in conjunction with aggregate functions such as SUM() or MIN(). For example let's say you have a table that has data on student name and test score. To find out the total score for each student you'll use the SUM() function together with the GROUP BY function as follows: SELECT student_name SUM(score) FROM test_scores GROUP BY student_name; HAVING is a condition that can be placed on top of an aggregate function. In the above example you can add  HAVING SUM(score) > 300 at the end of the query so the query only returns students whose total score is higher than 300.

Sam Hobbs · Answer

The following three C# Corner articles might also help. Group by and Order by Clause in SQL 2005 Grouping Sets in SQL Server 2008 SQL Optimization Tips

Vilas Gite · Answer

Hi Anilkumar please refer: http://www.sql-tutorial.net/SQL-HAVING.asp http://www.sql-tutorial.net/SQL-GROUP-BY.asp

Dorababu Meka · Answer

In simple GROUP BY combines those rows into groups HAVING filters groups check the following for reference and example http://www.w3schools.com/sql/sql_groupby.asp http://www.w3schools.com/sql/sql_having.asp