MySQL连接两个表并基于主键计数总记录

Question

I have two tables vendor and medicines on mysql database now i need to count total medicines transacted based on vendor ID with a condition status is equal to paid, in a single query and show it to my users

My vendor table looks like this

| ID |   vendor_name    |
+----+------------------+
|  1 | Marakel Medicine |
|  2 | Ignacio Pharmacy |
|  3 | Rico Medicines   |
|  4 | Marco Pharmacy   |
+----+------------------+

My Medicines table looks like this.

| ID | vendor_id | medicine_name  | Status  |
+----+-----------+----------------+---------+
|  1 |         1 | paracetamol #1 | paid    |
|  2 |         1 | paracetamol #1 | paid    |
|  3 |         2 | paracetamol #1 | pending |
|  4 |         2 | paracetamol #1 | paid    |
|  5 |         4 | paracetamol #1 | paid    |
+----+-----------+----------------+---------+

My desire output would be like this

+----+------------------+-----------+
| ID |   vendor_name    | Total Med |
+----+------------------+-----------+
|  1 | Marakel Medicine |         2 |
|  2 | Ignacio Pharmacy |         1 |
|  3 | Rico Medicines   |         0 |
|  4 | Marco Pharmacy   |         1 |
+----+------------------+-----------+

So far my code is below i was able to output per vendor i just don't have an idea how to count them based on there status, any suggestion would be great!

SELECT * FROM vendors LEFT JOIN medicine ON vendor.ID = medicines.vendor_id

Answer 1

Join Operation on tables based on status [paid or pending] & vendor name :

Proposed Query :

SELECT        vendor.ID, vendor.vendor_name, 
COUNT((CASE WHEN [status] <> 'pending' THEN 1 END)) AS 'Total Med'

FROM            medicines RIGHT OUTER JOIN
                vendor ON medicines.vendor_id = vendor.ID

GROUP BY vendor.vendor_name, vendor.ID

Note: This query has been worked out in MSSQL, you can refer the logic and try for MySQL.

Corresponding MySQL Syntax:

SELECT vendor.ID, vendor.vendor_name, 
COUNT((CASE WHEN status <> 'pending' THEN 1 END)) AS 'Total Med' 
FROM medicines 
RIGHT OUTER JOIN vendor ON 
medicines.vendor_id = vendor.ID GROUP BY vendor.vendor_name, vendor.ID

Answer 2

Use GROUP BY and COUNT

SELECT
    v.ID,
    v.vendor_name,
    COUNT(m.vendor_id) AS 'Total Med'
FROM
    vendors v
LEFT JOIN medicine m ON v.ID = m.vendor_id
GROUP BY
    v.ID

Answer 3

you should try this

SELECT v.ID,v.vendor_name,COUNT(m.ID) as `Total`
FROM vendor v LEFT JOIN medicines m ON v.ID=m.vendor_id
GROUP BY m.ID

Answer 4

MYSQL version of @tharif's MSSQL solution.

SELECT
    v.ID,
    v.vendor_name,
    COUNT((CASE WHEN m.`status` <> 'pending' THEN 1 END)) AS 'Total Med'
FROM
    vendor v
LEFT JOIN medicines m ON v.ID = m.vendor_id
GROUP BY v.ID

It is a good idea to read on group by and count if you are new to these.

Answer 5

Use Group By its an sql function and also use count its also an sql built in function..some similar shown below.

    SELECT vendors.id,vendors.vendor_name,COUNT(medicine.vendor_id) AS 'Total Transaction'
    FROM vendors LEFT JOIN medicine ON vendors.id = medicine.vendor_id 
    GROUP BY vendors.id