怎么统计表中的笔记? [英] How count notes from table?
问题描述
您好!我需要从表格菜单中显示标题类别并计算表格汽车中的注释,其中menu.id = cars.marka。所以,我想得到下一个:宝马(4),其中4是表汽车的票据数量。
我试过这样,但它不正确:
SELECT menu.title,COUNT(cars.id_cars) AS 总计
FROM 菜单
LEFT JOIN cars ON (cars.marka = menu.id AND 菜单。 parent_id = 96
AND menu.block = 3)
< blockquote>你需要一个 GROUP BY menu.title
语句让COUNT工作,
如下所示...
SELECT
menu.title,
COUNT(cars.id_cars) AS 总计
FROM
menu
LEFT JOIN
cars
ON (cars.marka = menu.id AND menu.parent_id = 96 AND menu.block = 3 )
GROUP BY menu.title
Jardin1写道:我想得到下一个:宝马(4),其中4是表汽车的票据数量。
在这种情况下你需要使用HAVING
子句如下:
DECLARE @ pid INT
DECLARE @ blo INT
DECLARE @ cou INT
SET @ pid = 96
SET @ blo = 3
< span class =code-keyword> SET @ cou = 4 - no。宝马;)
SELECT m.title
FROM menu AS m LEFT JOIN cars AS c ON c.marka = m.id
WHERE m.parent_id = @pid 和 m.block = @ blo
GROUP BY m.title
HAVING COUNT(c.id_cars)= @ cou
更多:
HAVING(T-SQL) [ ^ ]
GROUP BY(T-SQL) [ ^ ]
聚合函数(T -SQL) [ ^ ]
Hello! I need to show title categories from table Menu and count notes from table Cars, where menu.id = cars.marka. So, i wanna get the next: BMW (4), where 4 is number of notes from table Cars.
I tried such, but it not correct:
SELECT menu.title, COUNT( cars.id_cars ) AS total
FROM menu
LEFT JOIN cars ON (cars.marka = menu.id AND menu.parent_id =96
AND menu.block =3)
You need a GROUP BY menu.title
statement for the COUNT to work,
Do like below...
SELECT menu.title, COUNT(cars.id_cars) AS total FROM menu LEFT JOIN cars ON (cars.marka = menu.id AND menu.parent_id = 96 AND menu.block = 3) GROUP BY menu.title
Jardin1 wrote:i wanna get the next: BMW (4), where 4 is number of notes from table Cars.
In this case you need to useHAVING
clause as follow:
DECLARE @pid INT DECLARE @blo INT DECLARE @cou INT SET @pid = 96 SET @blo = 3 SET @cou = 4 --no. of BMW ;) SELECT m.title FROM menu AS m LEFT JOIN cars AS c ON c.marka = m.id WHERE m.parent_id =@pid AND m.block =@blo GROUP BY m.title HAVING COUNT(c.id_cars) = @cou
More:
HAVING (T-SQL)[^]
GROUP BY (T-SQL)[^]
Aggregate functions (T-SQL)[^]
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