HAVING अभिव्यक्ति को SQL में जोड़ा गया था क्योंकि WHERE कीवर्ड का उपयोग समग्र कार्यों के साथ नहीं किया जा सकता है।
SQL HAVING का उपयोग GROUP BY कथन द्वारा बनाए गए समूहों द्वारा मानों को फ़िल्टर करने के लिए किया जाता है।
SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
HAVING condition
ORDER BY column_name(s)
निम्नलिखित "Northwind" डेटाबेस की "Customers" ("ग्राहक") तालिका से एक नमूना है:
| CustomerID | CustomerName | ContactName | Address | City | PostalCode | Country |
|---|---|---|---|---|---|---|
| 1 | Alfreds Futterkiste | Maria Anders | Obere Str. 57 | Berlin | 12209 | Germany |
| 2 | Ana Trujillo Emparedados y helados | Ana Trujillo | Avda. de la Constitución 2222 | México D.F. | 5021 | Mexico |
| 3 | Antonio Moreno Taquería | Antonio Moreno | Mataderos 2312 | México D.F. | 5023 | Mexico |
| 4 | Around the Horn | Thomas Hardy | 120 Hanover Sq. | London | WA1 1DP | UK |
| 5 | Berglunds snabbköp | Christina Berglund | Berguvsvägen 8 | Luleå | S-958 22 | Sweden |
निम्नलिखित SQL क्वेरी प्रत्येक देश में ग्राहकों की संख्या सूचीबद्ध करती है। केवल 5 से अधिक ग्राहकों वाले देश शामिल हैं:
Run SQLSELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID) > 5
निम्नलिखित SQL क्वेरी प्रत्येक देश में ग्राहकों की संख्या को सबसे बड़े से सबसे छोटे क्रम में सूचीबद्ध करती है (इसमें केवल 5 से अधिक ग्राहकों वाले देश शामिल हैं):
Run SQLSELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID) > 5
ORDER BY COUNT(CustomerID) DESC
आइए तालिका "Orders" ("ऑर्डर") से एक नमूना देखें:
| ProductID | OrderID | CustomerID | EmployeeID | OrderDate | ShipperID |
|---|---|---|---|---|---|
| 1 | 10248 | 90 | 5 | 1996-07-04 | 3 |
| 2 | 10249 | 81 | 6 | 1996-07-05 | 1 |
| 3 | 10250 | 34 | 4 | 1996-07-08 | 2 |
| 4 | 10251 | 84 | 3 | 1996-07-08 | 1 |
| 5 | 10252 | 76 | 4 | 1996-07-09 | 2 |
और तालिका "Employees" ("कर्मचारी") से नमूना:
| EmployeeID | LastName | FirstName | BirthDate | Photo | Notes |
|---|---|---|---|---|---|
| 1 | Davolio | Nancy | 12/8/1968 | EmpID1.pic | Education includes a BA in psychology from Colorado State University. She also completed (The Art of the Cold Call). Nancy is a member of 'Toastmasters International'. |
| 2 | Fuller | Andrew | 2/19/1952 | EmpID2.pic | Andrew received his BTS commercial and a Ph.D. in international marketing from the University of Dallas. He is fluent in French and Italian and reads German. He joined the company as a sales representative, was promoted to sales manager and was then named vice president of sales. Andrew is a member of the Sales Management Roundtable, the Seattle Chamber of Commerce, and the Pacific Rim Importers Association. |
| 3 | Leverling | Janet | 8/30/1963 | EmpID3.pic | Janet has a BS degree in chemistry from Boston College). She has also completed a certificate program in food retailing management. Janet was hired as a sales associate and was promoted to sales representative. |
| 4 | Peacock | Margaret | 9/19/1958 | EmpID4.pic | Margaret holds a BA in English literature from Concordia College and an MA from the American Institute of Culinary Arts. She was temporarily assigned to the London office before returning to her permanent post in Seattle. |
| 5 | Buchanan | Steven | 3/4/1955 | EmpID5.pic | Steven Buchanan graduated from St. Andrews University, Scotland, with a BSC degree. Upon joining the company as a sales representative, he spent 6 months in an orientation program at the Seattle office and then returned to his permanent post in London, where he was promoted to sales manager. Mr. Buchanan has completed the courses 'Successful Telemarketing' and 'International Sales Management'. He is fluent in French. |
निम्नलिखित SQL क्वेरी उन कर्मचारियों को सूचीबद्ध करती है जिन्होंने 10 से अधिक ऑर्डर पंजीकृत किए हैं:
Run SQLSELECT Employees.LastName, COUNT(Orders.OrderID) AS NumberOfOrders
FROM (Orders
INNER JOIN Employees ON Orders.EmployeeID = Employees.EmployeeID)
GROUP BY LastName
HAVING COUNT(Orders.OrderID) > 10
यदि "डेवोलियो" या "फुलर" कर्मचारियों ने 25 से अधिक ऑर्डर पंजीकृत किए हैं, तो निम्न SQL कथन डेटा प्रदर्शित करता है:
Run SQLSELECT Employees.LastName, COUNT(Orders.OrderID) AS NumberOfOrders
FROM Orders
INNER JOIN Employees ON Orders.EmployeeID = Employees.EmployeeID
WHERE LastName = 'Davolio' OR LastName = 'Fuller'
GROUP BY LastName
HAVING COUNT(Orders.OrderID) > 25