SQL HAVING Clause

What does the HAVING clause do in a query?

The HAVING clause is like WHERE but operates on grouped records returned by a GROUP BY.
HAVING applies to summarized group records, whereas WHERE applies to individual records.
Only the groups that meet the HAVING criteria will be returned.

HAVING requires that a GROUP BY clause is present.
Both WHERE and HAVING can be used in the same query at the same time.

The SQL HAVING syntax

The general syntax is

SELECT column-names
  FROM table-name
 WHERE condition
 GROUP BY column-names
HAVING condition

The general syntax with ORDER BY is:

SELECT column-names
  FROM table-name
 WHERE condition
 GROUP BY column-names
HAVING condition
 ORDER BY column-names

CUSTOMER
Id
FirstName
LastName
City
Country
Phone

SQL GROUP BY Examples

Problem: List the number of customers in each country.
Only include countries with more than 10 customers.

SELECT COUNT(Id), Country 
  FROM Customer
 GROUP BY Country
HAVING COUNT(Id) > 10

Result: 3 records

Count	Country
11	France
11	Germany
13	USA

CUSTOMER
Id
FirstName
LastName
City
Country
Phone

Problem: List the number of customers in each country,
except the USA, sorted high to low.
Only include countries with 9 or more customers.

SELECT COUNT(Id), Country 
  FROM Customer
 WHERE Country <> 'USA'
 GROUP BY Country
HAVING COUNT(Id) >= 9
 ORDER BY COUNT(Id) DESC

Result: 3 records

Count	Country
11	France
11	Germany
9	Brazil

ORDER
Id
OrderDate
OrderNumber
CustomerId
TotalAmount

CUSTOMER
Id
FirstName
LastName
City
Country
Phone

Problem: List all customer with average orders
between $1000 and $1200.

SELECT AVG(TotalAmount), FirstName, LastName
  FROM [Order] O JOIN Customer C ON O.CustomerId = C.Id
 GROUP BY FirstName, LastName
HAVING AVG(TotalAmount) BETWEEN 1000 AND 1200

Result: 10 records

Average	FirstName	LastName
1081.215000	Miguel	Angel Paolino
1063.420000	Isabel	de Castro
1008.440000	Alexander	Feuer
1062.038461	Thomas	Hardy
1107.806666	Pirkko	Koskitalo
1174.945454	Janete	Limeira
1073.621428	Antonio	Moreno
1065.385000	Rita	Müller
1183.010000	José	Pedro Freyre
1057.386666	Carine	Schmitt