Question

我正在执行以下有一些语法错误的查询：

SELECT count (tbl_staff.staff_id as staff_number),SELECT count (tbl_client.client_id as client_number),SELECT count (tbl_appointment.appt_id             as appt_number),SELECT count (tbl_subscription.subscription_id as subscription_number)
FROM      tbl_subscription 
LEFT JOIN tbl_staff 
ON        ( 
                tbl_staff.merchant_id = tbl_subscription.merchant_id) 
LEFT JOIN tbl_appointment 
ON        ( 
                tbl_appointment.merchant_id = tbl_subscription.merchant_id) 
LEFT JOIN tbl_client 
ON        ( 
                tbl_client.merchant_id = tbl_subscription.merchant_id) 
WHERE     tbl_subscription.subscription_id=1;

我想在特定的Subscription_id上获取staff_id，client_d，appointment_id的计数。

Answer 1

您的选择列表已关闭，但有一些错误。也就是说，在查询中只需要一个SELECT（每个字段不需要一个），而“as ...”描述符属于括号外。

所以这部分查询

SELECT count (tbl_staff.staff_id as staff_number),
SELECT count (tbl_client.client_id as client_number),
SELECT count (tbl_appointment.appt_id as appt_number),
SELECT count (tbl_subscription.subscription_id as subscription_number)
FROM      tbl_subscription

会变成

SELECT count (tbl_staff.staff_id) as staff_number,
       count (tbl_client.client_id) as client_number,
       count (tbl_appointment.appt_id) as appt_number,
       count (tbl_subscription.subscription_id) as subscription_number
FROM      tbl_subscription

什么是正确的MySql查询？

1 个答案: