sqlite having 语句——迹忆客-ag捕鱼王app官网

having 子句允许指定条件来过滤将出现在最终结果中的分组结果。

where 子句在所选列上设置条件，而 having 子句则在由 group by 子句创建的分组上设置条件。

语法

下面是 having 子句在 select 查询中的位置：

select
from
where
group by
having
order by

在一个查询中，having 子句必须放在 group by 子句之后，必须放在 order by 子句之前。下面是包含 having 子句的 select 语句的语法：

select column1, column2
from table1, table2
where [ conditions ]
group by column1, column2
having [ conditions ]
order by column1, column2

示例

假设 company 表有以下记录：

id          name        age         address     salary
----------  ----------  ----------  ----------  ----------
1           paul        32          california  20000.0
2           allen       25          texas       15000.0
3           teddy       23          norway      20000.0
4           mark        25          rich-mond   65000.0
5           david       27          texas       85000.0
6           kim         22          south-hall  45000.0
7           james       24          houston     10000.0
8           paul        24          houston     20000.0
9           james       44          norway      5000.0
10          james       45          texas       5000.0

下面示例将显示名称计数小于 2 的所有记录：

sqlite > select * from company group by name having count(name) < 2;

结果如下：

id          name        age         address     salary
----------  ----------  ----------  ----------  ----------
2           allen       25          texas       15000
5           david       27          texas       85000
6           kim         22          south-hall  45000
4           mark        25          rich-mond   65000
3           teddy       23          norway      20000

下面示例将显示名称计数大于 2 的所有记录：

sqlite > select * from company group by name having count(name) > 2;

结果如下：

id          name        age         address     salary
----------  ----------  ----------  ----------  ----------
10          james       45          texas       5000