The SQL HAVING Clause – SQL ЭЗЭМШИХ нөхцөл #
The HAVING clause was added to SQL because the WHERE keyword cannot be used with aggregate functions.
HAVING нөхцөл нь SQL-д нэмэгдсэн бөгөөд учир нь WHERE түлхүүр үг нь нэгтгэл функцүүдтэй хамт ашиглагдах боломжгүй.
HAVING Syntax – HAVING Дүрэм #
SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
HAVING condition
ORDER BY column_name(s);SELECT багана_нэр(нүүд)
FROM хүснэгт_нэр
WHERE нөхцөл
GROUP BY багана_нэр(нүүд)
HAVING нөхцөл
ORDER BY багана_нэр(нүүд);Demo Database – Жишээ мэдээллийн сан #
Below is a selection from the “Customers” table:
Доорх жишээ нь “Харилцагчид” хүснэгтээс авсан хэсэг юм:
| 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. | 05021 | Mexico |
| 3 | Antonio Moreno Taquería | Antonio Moreno | Mataderos 2312 | México D.F. | 05023 | 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 |
SQL HAVING Examples – SQL HAVING жишээнүүд #
The following SQL statement lists the number of customers in each country. Only include countries with more than 5 customers:
Доорх SQL өгүүлбэр нь улс бүрт хэдэн харилцагч байгааг жагсаана. Зөвхөн 5-аас дээш харилцагчтай улсуудыг багтаана:
Example – Жишээ #
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID) > 5;
The following SQL statement lists the number of customers in each country, sorted high to low (Only include countries with more than 5 customers):
Доорх SQL өгүүлбэр нь улс бүрт хэдэн харилцагч байгааг ихээс бага руу эрэмбэлнэ (Зөвхөн 5-аас дээш харилцагчтай улсуудыг багтаана):
Example – Жишээ #
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID) > 5
ORDER BY COUNT(CustomerID) DESC;
Demo Database – Жишээ мэдээллийн сан #
Below is a selection from the “Orders” table:
Доорх жишээн нь “Захиалгууд” хүснэгтээс авсан хэсэг юм:
| OrderID | CustomerID | EmployeeID | OrderDate | ShipperID |
|---|---|---|---|---|
| 10248 | 90 | 5 | 1996-07-04 | 3 |
| 10249 | 81 | 6 | 1996-07-05 | 1 |
| 10250 | 34 | 4 | 1996-07-08 | 2 |
And a selection from the “Employees” table:
Бас “Ажилчид” хүснэгтээс авсан хэсэг:
| EmployeeID | LastName | FirstName | BirthDate | Photo | Notes |
|---|---|---|---|---|---|
| 1 | Davolio | Nancy | 1968-12-08 | EmpID1.pic | Education includes a BA…. |
| 2 | Fuller | Andrew | 1952-02-19 | EmpID2.pic | Andrew received his BTS…. |
| 3 | Leverling | Janet | 1963-08-30 | EmpID3.pic | Janet has a BS degree…. |
More HAVING Examples – HAVING нөхцөлтэй өөр жишээнүүд #
The following SQL statement lists the employees that have registered more than 10 orders:
Доорх SQL өгүүлбэр нь 10-аас дээш захиалга бүртгэсэн ажилчдыг жагсаана:
Example – Жишээ #
SELECT 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;
The following SQL statement lists if the employees “Davolio” or “Fuller” have registered more than 25 orders:
Доорх SQL өгүүлбэр нь “Davolio” эсвэл “Fuller” ажилчид 25-аас дээш захиалга бүртгэсэн эсэхийг харна:
Example – Жишээ #
SELECT 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;
