MySQL：怎样别离从列计数？

凡是我对SQL查询很是有信念,可是这个让我摸不着脑子.我认为这应该是一个快速修复,但我只是没有看到它.

我试图在一个查询中对统一个表上的多个值举办计数.

不要介怀“0000000000000000”,它只是暗示一个空字节数组.

有没有一种简朴的要领来组合这些查询？

SELECT COUNT(ssn)
FROM patients
WHERE ssn="0000000000000000";

SELECT COUNT(firstname)
FROM patients
WHERE firstname="0000000000000000"

SELECT COUNT(lastname)
FROM patients
WHERE lastname="0000000000000000"

etc...

SELECT COUNT(ssn) AS patient_count,'ssn' AS count_type
FROM patients
WHERE ssn="0000000000000000";
UNION
SELECT COUNT(firstname) AS patient_count,'firstname' AS count_type
FROM patients
WHERE firstname="0000000000000000"
UNION
SELECT COUNT(lastname) AS patient_count,'lastname' AS count_type
FROM patients
WHERE lastname="0000000000000000"

（编辑：湖南网）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!