I have a simple table of installs:
我有一个简单的安装表：
- prod_code
- prod_code
- 电子邮件
- install_slot
- install_slot
If the install_slot is NULL, then it's an available install slot. Not null -- then, used slot. I need to return a result of total installs for a given product and email, as well as a result of used installs for a given product and email. I guess I could do this with two queries, but wondered if there's a SQL way to do it all in one?
如果install_slot为NULL，那么它是一个可用的安装槽。不为null - 然后，使用插槽。我需要返回给定产品和电子邮件的总安装结果，以及给定产品和电子邮件的已安装结果。我想我可以用两个查询做到这一点，但想知道是否有一种SQL方法可以在一个中完成所有操作？
I tried the following as a wild guess, but it didn't work.
我尝试了以下作为一个疯狂的猜测，但它没有奏效。
SELECT
i1.`prod_code`,
COUNT(i1.`email`) AS total_installs,
COUNT(ISNULL(i2.`install_slot`)) AS used_installs
FROM
`installs` AS i1
JOIN
`installs` AS i2
ON
i1.`prod_code` = i2.`prod_code`
WHERE
i1.`email` = 'example@example.com'
GROUP BY
i1.`prod_code`,i2.`prod_code`
2 个解决方案
#1
25
SELECT prod_code,
COUNT(email) AS total_installs,
COUNT(install_slot) AS used_installs
FROM installs
WHERE email='example@example.com'
GROUP BY prod_code
COUNT counts NOT NULL values only.
COUNT仅计算NOT NULL值。
#2
3
The solution offered did not work for me. I had to modify as follows:
提供的解决方案对我不起作用。我不得不修改如下：
SELECT prod_code,
COUNT(NULLIF(email,'')) AS total_installs,
COUNT(NULLIF(install_slot,'')) AS used_installs
FROM installs
WHERE email='example@example.com'
GROUP BY prod_code
#1
25
SELECT prod_code,
COUNT(email) AS total_installs,
COUNT(install_slot) AS used_installs
FROM installs
WHERE email='example@example.com'
GROUP BY prod_code
COUNT counts NOT NULL values only.
COUNT仅计算NOT NULL值。
#2
3
The solution offered did not work for me. I had to modify as follows:
提供的解决方案对我不起作用。我不得不修改如下：
SELECT prod_code,
COUNT(NULLIF(email,'')) AS total_installs,
COUNT(NULLIF(install_slot,'')) AS used_installs
FROM installs
WHERE email='example@example.com'
GROUP BY prod_code