The SQL HAVING clause is used to restrict conditionally the output of a SQL statement, by a SQL aggregate function used in your SELECT list of columns.
You can't specify criteria in a SQL WHERE clause against a column in the SELECT list for which SQL aggregate function is used. For example the following SQL statement will generate an error:
SELECT Employee, SUM (Hours)
FROM EmployeeHours
WHERE SUM (Hours) > 24
GROUP BY Employee
The SQL HAVING clause is used to do exactly this, to specify a condition for an aggregate function which is used in your query:
SELECT Employee, SUM (Hours)
FROM EmployeeHours
GROUP BY Employee
HAVING SUM (Hours) > 24
The above SQL statement will select all employees and the sum of their respective hours, as long as this sum is greater than 24. The result of the SQL HAVING clause can be seen below:
Employee Hours
John Smith 25
Tina Crown 27
Popular Posts
-
The SQL AVG aggregate function selects the average value for certain table column. Have a look at the SQL AVG syntax: SELECT AVG(Column1) FR...
-
Namespaces Namespaces allow to group entities like classes, objects and functions under a name. This way the global scope can be divided in ...
-
package interfaceexercise; // Define an interface with three abstract methods. // Any class that implements this interface has to // impleme...
-
The SQL MAX aggregate function allows us to select the highest (maximum) value for a certain column. The SQL MAX function syntax is very sim...
-
Please do this exercise at the command line instead of using NetBeans. This is to learn the concept of packaging without the help of NetBean...
-
Tutorials Chapter 1 : What is SQL Server? Chapter 2 : Compare SQL Server and MS Access Chapter 3 : What is MSDE ? Chapter 4 : SQL Server Edi...
-
SQL Server (and SQL Server Express) supports two authentication modes: 1. Windows Authentication mode 2. Mixed Mode (Windows Authentication ... -
JavaServer Pages (JSP) lets you separate the dynamic part of your pages from the static HTML. You simply write the regular HTML in the norma...
-
The SQL SELECT INTO statement is used to select data from a SQL database table and to insert it to a different table at the same time. The g...
-
4.2 The Framework Class Library Now that you have a taste of the goals and groundwork laid by the CLR and managed code, let’s taste ...
No comments:
Post a Comment