SQL HAVING 子句
SQL HAVING 子句在 SQL 中增加 HAVING 子句原因是，WHERE 关键字无法与 Aggregate 函数一起使用。
HAVING子句已添加到SQL中，因为WHERE关键字不能用于聚合函数。
SQL HAVING 语法
SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
HAVING condition
ORDER BY column_name(s);
演示数据库
以下是罗斯文示例数据库中"Customers"表的选择：
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示例
以下SQL语句列出了每个国家/地区的客户数量。只包括超过5位客户的国家/地区：
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID) > 5;
以下SQL语句列出每个国家的客户数量，从高到低排序（仅包括拥有超过5名客户的国家/地区）：
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID) > 5
ORDER BY COUNT(CustomerID) DESC;
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