Mysql 当其他返回行的值为null=0时,如何显示其他查询行
我有一个三个表,我用它来左外连接以查看我所有的诊所名称,包括我需要的数据的总和和计数,我有下面的表截图: 现在,我这样提问:Mysql 当其他返回行的值为null=0时,如何显示其他查询行,mysql,database-design,left-join,coalesce,Mysql,Database Design,Left Join,Coalesce,我有一个三个表,我用它来左外连接以查看我所有的诊所名称,包括我需要的数据的总和和计数,我有下面的表截图: 现在,我这样提问: SELECT tbl_clinics.clinic_name, COALESCE(COUNT(tbl_check_up.check_up_id),0) AS totalpatient, COALESCE(SUM(tbl_bill.bill_amt),0) AS totalearn FROM tbl_clinics LEFT OUTER JOIN tbl_check_up
SELECT
tbl_clinics.clinic_name,
COALESCE(COUNT(tbl_check_up.check_up_id),0) AS totalpatient,
COALESCE(SUM(tbl_bill.bill_amt),0) AS totalearn
FROM
tbl_clinics
LEFT OUTER JOIN tbl_check_up ON tbl_clinics.clinic_id = tbl_check_up.clinic_id
LEFT OUTER JOIN tbl_bill ON tbl_bill.bill_id = tbl_check_up.bill_id
WHERE tbl_clinics.user_id = 102
我的查询输出如下:
问题:
现在,我的问题是我想通过显示空到零值来显示我的其他诊所。在我的数据中,我有3个诊所的用户_id=102,但为什么只有诊所1显示。我想要下面这样的输出,它显示tbl_check_up中没有与账单相同的诊所Id为2和3的值
+---------------+---------------+------------+
| Clinic Name | Total Patient | Total Earn |
+---------------+---------------+------------+
| Clinic 1 | 4 | 800.00 |
+---------------+---------------+------------+
| Clinic 2 | 0 | 0 |
+---------------+---------------+------------+
| Clinic 3 | 0 | 0 |
+---------------+---------------+------------+
这是您的查询(COALESCE()
对于COUNT()
)不是必需的):
我想你只需要
分组方式
只要分组方式
。
SELECT c.clinic_name,
COUNT(cu.check_up_id) AS totalpatient,
COALESCE(SUM(b.bill_amt), 0) AS totalearn
FROM tbl_clinics c LEFT OUTER JOIN
tbl_check_up cu
ON c.clinic_id = cu.clinic_id LEFT OUTER JOIN
tbl_bill b
ON b.bill_id = cu.bill_id
WHERE c.user_id = 102
GROUP BY c.clinic_name;