MySQL - 在 WHERE 子句中使用 COUNT(*)

Question

我正在尝试在 MySQL 中完成以下操作（参见

pseudo

代码）

SELECT DISTINCT gid
FROM `gd`
WHERE COUNT(*) > 10
ORDER BY lastupdated DESC

有没有办法在 WHERE 子句中不使用 (SELECT...) 来做到这一点，因为这看起来像是在浪费资源。

Answer 1

试试这个；

select gid
from `gd`
group by gid 
having count(*) > 10
order by lastupdated desc

Answer 2

我不确定你想做什么……也许是这样的

SELECT gid, COUNT(*) AS num FROM gd GROUP BY gid HAVING num > 10 ORDER BY lastupdated DESC

Answer 3

SELECT COUNT(*)
FROM `gd`
GROUP BY gid
HAVING COUNT(gid) > 10
ORDER BY lastupdated DESC;

编辑（如果你只想要 gids）：

SELECT MIN(gid)
FROM `gd`
GROUP BY gid
HAVING COUNT(gid) > 10
ORDER BY lastupdated DESC

Answer 4

只有学术版没有条款：

select *
from (
   select gid, count(*) as tmpcount from gd group by gid
) as tmp
where tmpcount > 10;

Answer 5

WHERE 子句中不能有聚合函数（例如 COUNT、MAX 等）。因此我们改用 HAVING 子句。因此整个查询将类似于：

SELECT column_name, aggregate_function(column_name)
FROM table_name
WHERE column_name operator value
GROUP BY column_name
HAVING aggregate_function(column_name) operator value;

Answer 6

试试

SELECT DISTINCT gid
FROM `gd`
group by gid
having count(*) > 10
ORDER BY max(lastupdated) DESC

Answer 7

COUNT(*)只能与HAVING一起使用，必须在GROUP BY之后使用 statement 请看下面的例子：

SELECT COUNT(*), M_Director.PID FROM Movie
INNER JOIN M_Director ON Movie.MID = M_Director.MID 
GROUP BY M_Director.PID
HAVING COUNT(*) > 10
ORDER BY COUNT(*) ASC

Answer 8

-- 寻找缺失半小时记录的气象站

SELECT stationid
FROM weather_data 
WHERE  `Timestamp` LIKE '2011-11-15 %'  AND 
stationid IN (SELECT `ID` FROM `weather_stations`)
GROUP BY stationid 
HAVING COUNT(*) != 48;

-- 带有 where .. in .. select 的 yapiskan 变体

Answer 9

我认为你不能用

count()

添加

where

。现在明白为什么....

where

与

having

不同，

having

表示您正在处理或处理组和计数的相同工作，它也在处理整个组，

现在如何算作整个团队工作

创建一个表并输入一些 id，然后使用：

select count(*) from table_name

你会发现total values表示它代表了一些组！所以

where

确实添加了

count()

；

Answer 10

SELECT DISTINCT gid
FROM `gd`
GROUP BY gid
HAVING COUNT(gid) > 10
ORDER BY lastupdated DESC;